diff --git a/pkg/mcp/agentic/dispatch.go b/pkg/mcp/agentic/dispatch.go
index 48985b4..349d3ae 100644
--- a/pkg/mcp/agentic/dispatch.go
+++ b/pkg/mcp/agentic/dispatch.go
@@ -4,17 +4,15 @@ package agentic
 
 import (
 	"context"
-	"fmt"
 	"os"
 	"os/exec"
-	"path/filepath"
-	"strings"
 	"syscall"
 	"time"
 
-	coremcp "dappco.re/go/mcp/pkg/mcp"
+	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
 	coreerr "dappco.re/go/core/log"
+	coremcp "dappco.re/go/mcp/pkg/mcp"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
@@ -54,7 +52,7 @@ func (s *PrepSubsystem) registerDispatchTool(svc *coremcp.Service) {
 // agentCommand returns the command and args for a given agent type.
 // Supports model variants: "gemini", "gemini:flash", "gemini:pro", "claude", "claude:haiku".
 func agentCommand(agent, prompt string) (string, []string, error) {
-	parts := strings.SplitN(agent, ":", 2)
+	parts := core.SplitN(agent, ":", 2)
 	base := parts[0]
 	model := ""
 	if len(parts) > 1 {
@@ -78,7 +76,7 @@ func agentCommand(agent, prompt string) (string, []string, error) {
 		return "claude", args, nil
 	case "local":
 		home, _ := os.UserHomeDir()
-		script := filepath.Join(home, "Code", "core", "agent", "scripts", "local-agent.sh")
+		script := core.Path(home, "Code", "core", "agent", "scripts", "local-agent.sh")
 		return "bash", []string{script, prompt}, nil
 	default:
 		return "", nil, coreerr.E("agentCommand", "unknown agent: "+agent, nil)
@@ -119,14 +117,14 @@ func (s *PrepSubsystem) dispatch(ctx context.Context, req *mcp.CallToolRequest,
 	}
 
 	wsDir := prepOut.WorkspaceDir
-	srcDir := filepath.Join(wsDir, "src")
+	srcDir := core.Path(wsDir, "src")
 
 	// The prompt is just: read PROMPT.md and do the work
 	prompt := "Read PROMPT.md for instructions. All context files (CLAUDE.md, TODO.md, CONTEXT.md, CONSUMERS.md, RECENT.md) are in the parent directory. Work in this directory."
 
 	if input.DryRun {
 		// Read PROMPT.md for the dry run output
-		promptRaw, _ := coreio.Local.Read(filepath.Join(wsDir, "PROMPT.md"))
+		promptRaw, _ := coreio.Local.Read(core.Path(wsDir, "PROMPT.md"))
 		return nil, DispatchOutput{
 			Success:      true,
 			Agent:        input.Agent,
@@ -181,7 +179,7 @@ func (s *PrepSubsystem) dispatch(ctx context.Context, req *mcp.CallToolRequest,
 		return nil, DispatchOutput{}, err
 	}
 
-	outputFile := filepath.Join(wsDir, fmt.Sprintf("agent-%s.log", input.Agent))
+	outputFile := core.Path(wsDir, core.Sprintf("agent-%s.log", input.Agent))
 	outFile, err := os.Create(outputFile)
 	if err != nil {
 		return nil, DispatchOutput{}, coreerr.E("dispatch", "failed to create log file", err)
@@ -247,7 +245,7 @@ func (s *PrepSubsystem) dispatch(ctx context.Context, req *mcp.CallToolRequest,
 		status := "completed"
 		channel := coremcp.ChannelAgentComplete
 		payload := map[string]any{
-			"workspace": filepath.Base(wsDir),
+			"workspace": core.PathBase(wsDir),
 			"repo":      input.Repo,
 			"org":       input.Org,
 			"agent":     input.Agent,
@@ -257,11 +255,11 @@ func (s *PrepSubsystem) dispatch(ctx context.Context, req *mcp.CallToolRequest,
 		// Update status to completed or blocked.
 		if st, err := readStatus(wsDir); err == nil {
 			st.PID = 0
-			if data, err := coreio.Local.Read(filepath.Join(wsDir, "src", "BLOCKED.md")); err == nil {
+			if data, err := coreio.Local.Read(core.Path(wsDir, "src", "BLOCKED.md")); err == nil {
 				status = "blocked"
 				channel = coremcp.ChannelAgentBlocked
 				st.Status = status
-				st.Question = strings.TrimSpace(data)
+				st.Question = core.Trim(data)
 				if st.Question != "" {
 					payload["question"] = st.Question
 				}
diff --git a/pkg/mcp/agentic/ingest.go b/pkg/mcp/agentic/ingest.go
index 5535e67..ca87761 100644
--- a/pkg/mcp/agentic/ingest.go
+++ b/pkg/mcp/agentic/ingest.go
@@ -3,10 +3,8 @@
 package agentic
 
 import (
-	"bytes"
 	"context"
 	"net/http"
-	"os"
 
 	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
@@ -96,26 +94,22 @@ func (s *PrepSubsystem) createIssueViaAPI(repo, title, description, issueType, p
 	}
 
 	// Read the agent API key from file
-	home, _ := os.UserHomeDir()
+	home := core.Env("HOME")
 	apiKeyData, err := coreio.Local.Read(core.Path(home, ".claude", "agent-api.key"))
 	if err != nil {
 		return false
 	}
 	apiKey := core.Trim(apiKeyData)
 
-	r := core.JSONMarshal(map[string]string{
+	payloadStr := core.JSONMarshalString(map[string]string{
 		"title":       title,
 		"description": description,
 		"type":        issueType,
 		"priority":    priority,
 		"reporter":    "cladius",
 	})
-	if !r.OK {
-		return false
-	}
-	payload := r.Value.([]byte)
 
-	req, err := http.NewRequest("POST", s.brainURL+"/v1/issues", bytes.NewReader(payload))
+	req, err := http.NewRequest("POST", s.brainURL+"/v1/issues", core.NewReader(payloadStr))
 	if err != nil {
 		return false
 	}
diff --git a/pkg/mcp/agentic/mirror.go b/pkg/mcp/agentic/mirror.go
index 4799d1b..708c99c 100644
--- a/pkg/mcp/agentic/mirror.go
+++ b/pkg/mcp/agentic/mirror.go
@@ -4,12 +4,11 @@ package agentic
 
 import (
 	"context"
-	"fmt"
 	"os/exec"
-	"path/filepath"
 
-	coremcp "dappco.re/go/mcp/pkg/mcp"
+	core "dappco.re/go/core"
 	coreerr "dappco.re/go/core/log"
+	coremcp "dappco.re/go/mcp/pkg/mcp"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
@@ -64,7 +63,7 @@ func (s *PrepSubsystem) mirror(ctx context.Context, _ *mcp.CallToolRequest, inpu
 	skipped := make([]string, 0)
 
 	for _, repo := range repos {
-		repoDir := filepath.Join(basePath, repo)
+		repoDir := core.Path(basePath, repo)
 		if !hasRemote(repoDir, "github") {
 			skipped = append(skipped, repo+": no github remote")
 			continue
@@ -88,7 +87,7 @@ func (s *PrepSubsystem) mirror(ctx context.Context, _ *mcp.CallToolRequest, inpu
 		}
 
 		if files > maxFiles {
-			sync.Skipped = fmt.Sprintf("%d files exceeds limit of %d", files, maxFiles)
+			sync.Skipped = core.Sprintf("%d files exceeds limit of %d", files, maxFiles)
 			synced = append(synced, sync)
 			continue
 		}
diff --git a/pkg/mcp/agentic/plan.go b/pkg/mcp/agentic/plan.go
index 223a2da..e872069 100644
--- a/pkg/mcp/agentic/plan.go
+++ b/pkg/mcp/agentic/plan.go
@@ -7,7 +7,6 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"encoding/json"
-	"strings"
 	"time"
 
 	core "dappco.re/go/core"
@@ -430,33 +429,33 @@ func planPath(dir, id string) string {
 }
 
 func generatePlanID(title string) string {
-	slug := strings.Map(func(r rune) rune {
-		if r >= 'a' && r <= 'z' || r >= '0' && r <= '9' || r == '-' {
-			return r
+	b := core.NewBuilder()
+	b.Grow(len(title))
+	for _, r := range title {
+		switch {
+		case r >= 'a' && r <= 'z', r >= '0' && r <= '9', r == '-':
+			b.WriteRune(r)
+		case r >= 'A' && r <= 'Z':
+			b.WriteRune(r + 32)
+		case r == ' ':
+			b.WriteByte('-')
 		}
-		if r >= 'A' && r <= 'Z' {
-			return r + 32
-		}
-		if r == ' ' {
-			return '-'
-		}
-		return -1
-	}, title)
+	}
+	slug := b.String()
 
-	// Trim consecutive dashes and cap length
+	// Collapse consecutive dashes and cap length
 	for core.Contains(slug, "--") {
 		slug = core.Replace(slug, "--", "-")
 	}
-	slug = strings.Trim(slug, "-")
+	slug = trimDashes(slug)
 	if len(slug) > 30 {
-		slug = slug[:30]
+		slug = trimDashes(slug[:30])
 	}
-	slug = strings.TrimRight(slug, "-")
 
 	// Append short random suffix for uniqueness
-	b := make([]byte, 3)
-	rand.Read(b)
-	return slug + "-" + hex.EncodeToString(b)
+	rnd := make([]byte, 3)
+	rand.Read(rnd)
+	return slug + "-" + hex.EncodeToString(rnd)
 }
 
 func readPlan(dir, id string) (*Plan, error) {
diff --git a/pkg/mcp/agentic/pr.go b/pkg/mcp/agentic/pr.go
index 94996e9..9f624b0 100644
--- a/pkg/mcp/agentic/pr.go
+++ b/pkg/mcp/agentic/pr.go
@@ -6,15 +6,13 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
-	"fmt"
 	"net/http"
 	"os/exec"
-	"path/filepath"
-	"strings"
 
-	coremcp "dappco.re/go/mcp/pkg/mcp"
+	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
 	coreerr "dappco.re/go/core/log"
+	coremcp "dappco.re/go/mcp/pkg/mcp"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
@@ -66,8 +64,8 @@ func (s *PrepSubsystem) createPR(ctx context.Context, _ *mcp.CallToolRequest, in
 		return nil, CreatePROutput{}, coreerr.E("createPR", "no Forge token configured", nil)
 	}
 
-	wsDir := filepath.Join(s.workspaceRoot(), input.Workspace)
-	srcDir := filepath.Join(wsDir, "src")
+	wsDir := core.Path(s.workspaceRoot(), input.Workspace)
+	srcDir := core.Path(wsDir, "src")
 
 	if _, err := coreio.Local.List(srcDir); err != nil {
 		return nil, CreatePROutput{}, coreerr.E("createPR", "workspace not found: "+input.Workspace, nil)
@@ -87,7 +85,7 @@ func (s *PrepSubsystem) createPR(ctx context.Context, _ *mcp.CallToolRequest, in
 		if err != nil {
 			return nil, CreatePROutput{}, coreerr.E("createPR", "failed to detect branch", err)
 		}
-		st.Branch = strings.TrimSpace(string(out))
+		st.Branch = core.Trim(string(out))
 	}
 
 	org := st.Org
@@ -105,7 +103,7 @@ func (s *PrepSubsystem) createPR(ctx context.Context, _ *mcp.CallToolRequest, in
 		title = st.Task
 	}
 	if title == "" {
-		title = fmt.Sprintf("Agent work on %s", st.Branch)
+		title = core.Sprintf("Agent work on %s", st.Branch)
 	}
 
 	// Build PR body
@@ -143,7 +141,7 @@ func (s *PrepSubsystem) createPR(ctx context.Context, _ *mcp.CallToolRequest, in
 
 	// Comment on issue if tracked
 	if st.Issue > 0 {
-		comment := fmt.Sprintf("Pull request created: %s", prURL)
+		comment := core.Sprintf("Pull request created: %s", prURL)
 		s.commentOnIssue(ctx, org, st.Repo, st.Issue, comment)
 	}
 
@@ -159,17 +157,17 @@ func (s *PrepSubsystem) createPR(ctx context.Context, _ *mcp.CallToolRequest, in
 }
 
 func (s *PrepSubsystem) buildPRBody(st *WorkspaceStatus) string {
-	var b strings.Builder
+	b := core.NewBuilder()
 	b.WriteString("## Summary\n\n")
 	if st.Task != "" {
 		b.WriteString(st.Task)
 		b.WriteString("\n\n")
 	}
 	if st.Issue > 0 {
-		b.WriteString(fmt.Sprintf("Closes #%d\n\n", st.Issue))
+		b.WriteString(core.Sprintf("Closes #%d\n\n", st.Issue))
 	}
-	b.WriteString(fmt.Sprintf("**Agent:** %s\n", st.Agent))
-	b.WriteString(fmt.Sprintf("**Runs:** %d\n", st.Runs))
+	b.WriteString(core.Sprintf("**Agent:** %s\n", st.Agent))
+	b.WriteString(core.Sprintf("**Runs:** %d\n", st.Runs))
 	b.WriteString("\n---\n*Created by agentic dispatch*\n")
 	return b.String()
 }
@@ -185,7 +183,7 @@ func (s *PrepSubsystem) forgeCreatePR(ctx context.Context, org, repo, head, base
 		return "", 0, coreerr.E("forgeCreatePR", "failed to marshal PR payload", err)
 	}
 
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls", s.forgeURL, org, repo)
+	url := core.Sprintf("%s/api/v1/repos/%s/%s/pulls", s.forgeURL, org, repo)
 	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(payload))
 	if err != nil {
 		return "", 0, coreerr.E("forgeCreatePR", "failed to build PR request", err)
@@ -202,10 +200,10 @@ func (s *PrepSubsystem) forgeCreatePR(ctx context.Context, org, repo, head, base
 	if resp.StatusCode != 201 {
 		var errBody map[string]any
 		if err := json.NewDecoder(resp.Body).Decode(&errBody); err != nil {
-			return "", 0, coreerr.E("forgeCreatePR", fmt.Sprintf("HTTP %d with unreadable error body", resp.StatusCode), err)
+			return "", 0, coreerr.E("forgeCreatePR", core.Sprintf("HTTP %d with unreadable error body", resp.StatusCode), err)
 		}
 		msg, _ := errBody["message"].(string)
-		return "", 0, coreerr.E("forgeCreatePR", fmt.Sprintf("HTTP %d: %s", resp.StatusCode, msg), nil)
+		return "", 0, coreerr.E("forgeCreatePR", core.Sprintf("HTTP %d: %s", resp.StatusCode, msg), nil)
 	}
 
 	var pr struct {
@@ -225,7 +223,7 @@ func (s *PrepSubsystem) commentOnIssue(ctx context.Context, org, repo string, is
 		return
 	}
 
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/issues/%d/comments", s.forgeURL, org, repo, issue)
+	url := core.Sprintf("%s/api/v1/repos/%s/%s/issues/%d/comments", s.forgeURL, org, repo, issue)
 	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(payload))
 	if err != nil {
 		return
@@ -337,7 +335,7 @@ func (s *PrepSubsystem) listPRs(ctx context.Context, _ *mcp.CallToolRequest, inp
 }
 
 func (s *PrepSubsystem) listRepoPRs(ctx context.Context, org, repo, state string) ([]PRInfo, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls?state=%s&limit=10",
+	url := core.Sprintf("%s/api/v1/repos/%s/%s/pulls?state=%s&limit=10",
 		s.forgeURL, org, repo, state)
 	req, _ := http.NewRequestWithContext(ctx, "GET", url, nil)
 	req.Header.Set("Authorization", "token "+s.forgeToken)
@@ -348,7 +346,7 @@ func (s *PrepSubsystem) listRepoPRs(ctx context.Context, org, repo, state string
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode != 200 {
-		return nil, coreerr.E("listRepoPRs", fmt.Sprintf("HTTP %d for "+repo, resp.StatusCode), nil)
+		return nil, coreerr.E("listRepoPRs", core.Sprintf("HTTP %d for "+repo, resp.StatusCode), nil)
 	}
 
 	var prs []struct {
diff --git a/pkg/mcp/agentic/prep.go b/pkg/mcp/agentic/prep.go
index 4b0bcc2..71ca64e 100644
--- a/pkg/mcp/agentic/prep.go
+++ b/pkg/mcp/agentic/prep.go
@@ -8,18 +8,14 @@ import (
 	"context"
 	"encoding/base64"
 	"encoding/json"
-	"fmt"
-	goio "io"
 	"net/http"
-	"os"
 	"os/exec"
-	"path/filepath"
-	"strings"
 	"time"
 
-	coremcp "dappco.re/go/mcp/pkg/mcp"
+	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
 	coreerr "dappco.re/go/core/log"
+	coremcp "dappco.re/go/mcp/pkg/mcp"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 	"gopkg.in/yaml.v3"
 )
@@ -46,17 +42,17 @@ var (
 //
 //	prep := NewPrep()
 func NewPrep() *PrepSubsystem {
-	home, _ := os.UserHomeDir()
+	home := core.Env("HOME")
 
-	forgeToken := os.Getenv("FORGE_TOKEN")
+	forgeToken := core.Env("FORGE_TOKEN")
 	if forgeToken == "" {
-		forgeToken = os.Getenv("GITEA_TOKEN")
+		forgeToken = core.Env("GITEA_TOKEN")
 	}
 
-	brainKey := os.Getenv("CORE_BRAIN_KEY")
+	brainKey := core.Env("CORE_BRAIN_KEY")
 	if brainKey == "" {
-		if data, err := coreio.Local.Read(filepath.Join(home, ".claude", "brain.key")); err == nil {
-			brainKey = strings.TrimSpace(data)
+		if data, err := coreio.Local.Read(core.Path(home, ".claude", "brain.key")); err == nil {
+			brainKey = core.Trim(data)
 		}
 	}
 
@@ -65,8 +61,8 @@ func NewPrep() *PrepSubsystem {
 		forgeToken: forgeToken,
 		brainURL:   envOr("CORE_BRAIN_URL", "https://api.lthn.sh"),
 		brainKey:   brainKey,
-		specsPath:  envOr("SPECS_PATH", filepath.Join(home, "Code", "host-uk", "specs")),
-		codePath:   envOr("CODE_PATH", filepath.Join(home, "Code")),
+		specsPath:  envOr("SPECS_PATH", core.Path(home, "Code", "host-uk", "specs")),
+		codePath:   envOr("CODE_PATH", core.Path(home, "Code")),
 		client:     &http.Client{Timeout: 30 * time.Second},
 	}
 }
@@ -84,24 +80,24 @@ func (s *PrepSubsystem) emitChannel(ctx context.Context, channel string, data an
 }
 
 func envOr(key, fallback string) string {
-	if v := os.Getenv(key); v != "" {
+	if v := core.Env(key); v != "" {
 		return v
 	}
 	return fallback
 }
 
 func sanitizeRepoPathSegment(value, field string, allowSubdirs bool) (string, error) {
-	if strings.TrimSpace(value) != value {
+	if core.Trim(value) != value {
 		return "", coreerr.E("prepWorkspace", field+" contains whitespace", nil)
 	}
 	if value == "" {
 		return "", nil
 	}
-	if strings.Contains(value, "\\") {
+	if core.Contains(value, "\\") {
 		return "", coreerr.E("prepWorkspace", field+" contains invalid path separator", nil)
 	}
 
-	parts := strings.Split(value, "/")
+	parts := core.Split(value, "/")
 	if !allowSubdirs && len(parts) != 1 {
 		return "", coreerr.E("prepWorkspace", field+" may not contain subdirectories", nil)
 	}
@@ -161,7 +157,7 @@ func (s *PrepSubsystem) Shutdown(_ context.Context) error { return nil }
 
 // workspaceRoot returns the base directory for agent workspaces.
 func (s *PrepSubsystem) workspaceRoot() string {
-	return filepath.Join(s.codePath, ".core", "workspace")
+	return core.Path(s.codePath, ".core", "workspace")
 }
 
 // --- Input/Output types ---
@@ -227,8 +223,8 @@ func (s *PrepSubsystem) prepWorkspace(ctx context.Context, _ *mcp.CallToolReques
 	// Workspace root: .core/workspace/{repo}-{timestamp}/
 	wsRoot := s.workspaceRoot()
 	coreio.Local.EnsureDir(wsRoot)
-	wsName := fmt.Sprintf("%s-%d", input.Repo, time.Now().Unix())
-	wsDir := filepath.Join(wsRoot, wsName)
+	wsName := core.Sprintf("%s-%d", input.Repo, time.Now().Unix())
+	wsDir := core.Path(wsRoot, wsName)
 
 	// Create workspace structure
 	// kb/ and specs/ will be created inside src/ after clone
@@ -236,10 +232,10 @@ func (s *PrepSubsystem) prepWorkspace(ctx context.Context, _ *mcp.CallToolReques
 	out := PrepOutput{WorkspaceDir: wsDir}
 
 	// Source repo path
-	repoPath := filepath.Join(s.codePath, "core", input.Repo)
+	repoPath := core.Path(s.codePath, "core", input.Repo)
 
 	// 1. Clone repo into src/ and create feature branch
-	srcDir := filepath.Join(wsDir, "src")
+	srcDir := core.Path(wsDir, "src")
 	cloneCmd := exec.CommandContext(ctx, "git", "clone", repoPath, srcDir)
 	if err := cloneCmd.Run(); err != nil {
 		return nil, PrepOutput{}, coreerr.E("prepWorkspace", "failed to clone repository", err)
@@ -251,12 +247,12 @@ func (s *PrepSubsystem) prepWorkspace(ctx context.Context, _ *mcp.CallToolReques
 		taskSlug := branchSlug(input.Task)
 		if input.Issue > 0 {
 			issueSlug := branchSlug(input.Task)
-			branchName = fmt.Sprintf("agent/issue-%d", input.Issue)
+			branchName = core.Sprintf("agent/issue-%d", input.Issue)
 			if issueSlug != "" {
 				branchName += "-" + issueSlug
 			}
 		} else if taskSlug != "" {
-			branchName = fmt.Sprintf("agent/%s", taskSlug)
+			branchName = core.Sprintf("agent/%s", taskSlug)
 		}
 	}
 	if branchName != "" {
@@ -269,29 +265,29 @@ func (s *PrepSubsystem) prepWorkspace(ctx context.Context, _ *mcp.CallToolReques
 	}
 
 	// Create context dirs inside src/
-	coreio.Local.EnsureDir(filepath.Join(srcDir, "kb"))
-	coreio.Local.EnsureDir(filepath.Join(srcDir, "specs"))
+	coreio.Local.EnsureDir(core.Path(srcDir, "kb"))
+	coreio.Local.EnsureDir(core.Path(srcDir, "specs"))
 
 	// Remote stays as local clone origin — agent cannot push to forge.
 	// Reviewer pulls changes from workspace and pushes after verification.
 
 	// 2. Copy CLAUDE.md and GEMINI.md to workspace
-	claudeMdPath := filepath.Join(repoPath, "CLAUDE.md")
+	claudeMdPath := core.Path(repoPath, "CLAUDE.md")
 	if data, err := coreio.Local.Read(claudeMdPath); err == nil {
-		_ = writeAtomic(filepath.Join(wsDir, "src", "CLAUDE.md"), data)
+		_ = writeAtomic(core.Path(wsDir, "src", "CLAUDE.md"), data)
 		out.ClaudeMd = true
 	}
 	// Copy GEMINI.md from core/agent (ethics framework for all agents)
-	agentGeminiMd := filepath.Join(s.codePath, "core", "agent", "GEMINI.md")
+	agentGeminiMd := core.Path(s.codePath, "core", "agent", "GEMINI.md")
 	if data, err := coreio.Local.Read(agentGeminiMd); err == nil {
-		_ = writeAtomic(filepath.Join(wsDir, "src", "GEMINI.md"), data)
+		_ = writeAtomic(core.Path(wsDir, "src", "GEMINI.md"), data)
 	}
 
 	// Copy persona if specified
 	if persona != "" {
-		personaPath := filepath.Join(s.codePath, "core", "agent", "prompts", "personas", persona+".md")
+		personaPath := core.Path(s.codePath, "core", "agent", "prompts", "personas", persona+".md")
 		if data, err := coreio.Local.Read(personaPath); err == nil {
-			_ = writeAtomic(filepath.Join(wsDir, "src", "PERSONA.md"), data)
+			_ = writeAtomic(core.Path(wsDir, "src", "PERSONA.md"), data)
 		}
 	}
 
@@ -299,9 +295,9 @@ func (s *PrepSubsystem) prepWorkspace(ctx context.Context, _ *mcp.CallToolReques
 	if input.Issue > 0 {
 		s.generateTodo(ctx, input.Org, input.Repo, input.Issue, wsDir)
 	} else if input.Task != "" {
-		todo := fmt.Sprintf("# TASK: %s\n\n**Repo:** %s/%s\n**Status:** ready\n\n## Objective\n\n%s\n",
+		todo := core.Sprintf("# TASK: %s\n\n**Repo:** %s/%s\n**Status:** ready\n\n## Objective\n\n%s\n",
 			input.Task, input.Org, input.Repo, input.Task)
-		_ = writeAtomic(filepath.Join(wsDir, "src", "TODO.md"), todo)
+		_ = writeAtomic(core.Path(wsDir, "src", "TODO.md"), todo)
 	}
 
 	// 4. Generate CONTEXT.md from OpenBrain
@@ -333,12 +329,12 @@ func (s *PrepSubsystem) prepWorkspace(ctx context.Context, _ *mcp.CallToolReques
 
 // branchSlug converts a free-form string into a git-friendly branch suffix.
 func branchSlug(value string) string {
-	value = strings.ToLower(strings.TrimSpace(value))
+	value = core.Lower(core.Trim(value))
 	if value == "" {
 		return ""
 	}
 
-	var b strings.Builder
+	b := core.NewBuilder()
 	b.Grow(len(value))
 	lastDash := false
 	for _, r := range value {
@@ -359,14 +355,42 @@ func branchSlug(value string) string {
 		}
 	}
 
-	slug := strings.Trim(b.String(), "-")
+	slug := trimDashes(b.String())
 	if len(slug) > 40 {
-		slug = slug[:40]
-		slug = strings.Trim(slug, "-")
+		slug = trimDashes(slug[:40])
 	}
 	return slug
 }
 
+// sanitizeFilename replaces non-alphanumeric characters (except - _ .) with dashes.
+func sanitizeFilename(title string) string {
+	b := core.NewBuilder()
+	b.Grow(len(title))
+	for _, r := range title {
+		switch {
+		case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r >= '0' && r <= '9',
+			r == '-', r == '_', r == '.':
+			b.WriteRune(r)
+		default:
+			b.WriteByte('-')
+		}
+	}
+	return b.String()
+}
+
+// trimDashes strips leading and trailing dash characters from a string.
+func trimDashes(s string) string {
+	start := 0
+	for start < len(s) && s[start] == '-' {
+		start++
+	}
+	end := len(s)
+	for end > start && s[end-1] == '-' {
+		end--
+	}
+	return s[start:end]
+}
+
 // --- Prompt templates ---
 
 func (s *PrepSubsystem) writePromptTemplate(template, wsDir string) {
@@ -434,7 +458,7 @@ Do NOT push. Commit only — a reviewer will verify and push.
 		prompt = "Read TODO.md and complete the task. Work in src/.\n"
 	}
 
-	_ = writeAtomic(filepath.Join(wsDir, "src", "PROMPT.md"), prompt)
+	_ = writeAtomic(core.Path(wsDir, "src", "PROMPT.md"), prompt)
 }
 
 // --- Plan template rendering ---
@@ -443,11 +467,11 @@ Do NOT push. Commit only — a reviewer will verify and push.
 // and writes PLAN.md into the workspace src/ directory.
 func (s *PrepSubsystem) writePlanFromTemplate(templateSlug string, variables map[string]string, task string, wsDir string) {
 	// Look for template in core/agent/prompts/templates/
-	templatePath := filepath.Join(s.codePath, "core", "agent", "prompts", "templates", templateSlug+".yaml")
+	templatePath := core.Path(s.codePath, "core", "agent", "prompts", "templates", templateSlug+".yaml")
 	content, err := coreio.Local.Read(templatePath)
 	if err != nil {
 		// Try .yml extension
-		templatePath = filepath.Join(s.codePath, "core", "agent", "prompts", "templates", templateSlug+".yml")
+		templatePath = core.Path(s.codePath, "core", "agent", "prompts", "templates", templateSlug+".yml")
 		content, err = coreio.Local.Read(templatePath)
 		if err != nil {
 			return // Template not found, skip silently
@@ -456,8 +480,8 @@ func (s *PrepSubsystem) writePlanFromTemplate(templateSlug string, variables map
 
 	// Substitute variables ({{variable_name}} → value)
 	for key, value := range variables {
-		content = strings.ReplaceAll(content, "{{"+key+"}}", value)
-		content = strings.ReplaceAll(content, "{{ "+key+" }}", value)
+		content = core.Replace(content, "{{"+key+"}}", value)
+		content = core.Replace(content, "{{ "+key+" }}", value)
 	}
 
 	// Parse the YAML to render as markdown
@@ -477,7 +501,7 @@ func (s *PrepSubsystem) writePlanFromTemplate(templateSlug string, variables map
 	}
 
 	// Render as PLAN.md
-	var plan strings.Builder
+	plan := core.NewBuilder()
 	plan.WriteString("# Plan: " + tmpl.Name + "\n\n")
 	if task != "" {
 		plan.WriteString("**Task:** " + task + "\n\n")
@@ -495,7 +519,7 @@ func (s *PrepSubsystem) writePlanFromTemplate(templateSlug string, variables map
 	}
 
 	for i, phase := range tmpl.Phases {
-		plan.WriteString(fmt.Sprintf("## Phase %d: %s\n\n", i+1, phase.Name))
+		plan.WriteString(core.Sprintf("## Phase %d: %s\n\n", i+1, phase.Name))
 		if phase.Description != "" {
 			plan.WriteString(phase.Description + "\n\n")
 		}
@@ -512,7 +536,7 @@ func (s *PrepSubsystem) writePlanFromTemplate(templateSlug string, variables map
 		plan.WriteString("\n**Commit after completing this phase.**\n\n---\n\n")
 	}
 
-	_ = writeAtomic(filepath.Join(wsDir, "src", "PLAN.md"), plan.String())
+	_ = writeAtomic(core.Path(wsDir, "src", "PLAN.md"), plan.String())
 }
 
 // --- Helpers (unchanged) ---
@@ -522,7 +546,7 @@ func (s *PrepSubsystem) pullWiki(ctx context.Context, org, repo, wsDir string) i
 		return 0
 	}
 
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/wiki/pages", s.forgeURL, org, repo)
+	url := core.Sprintf("%s/api/v1/repos/%s/%s/wiki/pages", s.forgeURL, org, repo)
 	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
 	if err != nil {
 		return 0
@@ -553,7 +577,7 @@ func (s *PrepSubsystem) pullWiki(ctx context.Context, org, repo, wsDir string) i
 			subURL = page.Title
 		}
 
-		pageURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/wiki/page/%s", s.forgeURL, org, repo, subURL)
+		pageURL := core.Sprintf("%s/api/v1/repos/%s/%s/wiki/page/%s", s.forgeURL, org, repo, subURL)
 		pageReq, err := http.NewRequestWithContext(ctx, "GET", pageURL, nil)
 		if err != nil {
 			continue
@@ -585,14 +609,9 @@ func (s *PrepSubsystem) pullWiki(ctx context.Context, org, repo, wsDir string) i
 		if err != nil {
 			continue
 		}
-		filename := strings.Map(func(r rune) rune {
-			if r >= 'a' && r <= 'z' || r >= 'A' && r <= 'Z' || r >= '0' && r <= '9' || r == '-' || r == '_' || r == '.' {
-				return r
-			}
-			return '-'
-		}, page.Title) + ".md"
+		filename := sanitizeFilename(page.Title) + ".md"
 
-		_ = writeAtomic(filepath.Join(wsDir, "src", "kb", filename), string(content))
+		_ = writeAtomic(core.Path(wsDir, "src", "kb", filename), string(content))
 		count++
 	}
 
@@ -604,9 +623,9 @@ func (s *PrepSubsystem) copySpecs(wsDir string) int {
 	count := 0
 
 	for _, file := range specFiles {
-		src := filepath.Join(s.specsPath, file)
+		src := core.Path(s.specsPath, file)
 		if data, err := coreio.Local.Read(src); err == nil {
-			_ = writeAtomic(filepath.Join(wsDir, "src", "specs", file), data)
+			_ = writeAtomic(core.Path(wsDir, "src", "specs", file), data)
 			count++
 		}
 	}
@@ -629,7 +648,7 @@ func (s *PrepSubsystem) generateContext(ctx context.Context, repo, wsDir string)
 		return 0
 	}
 
-	req, err := http.NewRequestWithContext(ctx, "POST", s.brainURL+"/v1/brain/recall", strings.NewReader(string(body)))
+	req, err := http.NewRequestWithContext(ctx, "POST", s.brainURL+"/v1/brain/recall", core.NewReader(string(body)))
 	if err != nil {
 		return 0
 	}
@@ -646,18 +665,18 @@ func (s *PrepSubsystem) generateContext(ctx context.Context, repo, wsDir string)
 		return 0
 	}
 
-	respData, err := goio.ReadAll(resp.Body)
-	if err != nil {
+	readResult := core.ReadAll(resp.Body)
+	if !readResult.OK {
 		return 0
 	}
 	var result struct {
 		Memories []map[string]any `json:"memories"`
 	}
-	if err := json.Unmarshal(respData, &result); err != nil {
+	if ur := core.JSONUnmarshal([]byte(readResult.Value.(string)), &result); !ur.OK {
 		return 0
 	}
 
-	var content strings.Builder
+	content := core.NewBuilder()
 	content.WriteString("# Context — " + repo + "\n\n")
 	content.WriteString("> Relevant knowledge from OpenBrain.\n\n")
 
@@ -666,15 +685,15 @@ func (s *PrepSubsystem) generateContext(ctx context.Context, repo, wsDir string)
 		memContent, _ := mem["content"].(string)
 		memProject, _ := mem["project"].(string)
 		score, _ := mem["score"].(float64)
-		content.WriteString(fmt.Sprintf("### %d. %s [%s] (score: %.3f)\n\n%s\n\n", i+1, memProject, memType, score, memContent))
+		content.WriteString(core.Sprintf("### %d. %s [%s] (score: %.3f)\n\n%s\n\n", i+1, memProject, memType, score, memContent))
 	}
 
-	_ = writeAtomic(filepath.Join(wsDir, "src", "CONTEXT.md"), content.String())
+	_ = writeAtomic(core.Path(wsDir, "src", "CONTEXT.md"), content.String())
 	return len(result.Memories)
 }
 
 func (s *PrepSubsystem) findConsumers(repo, wsDir string) int {
-	goWorkPath := filepath.Join(s.codePath, "go.work")
+	goWorkPath := core.Path(s.codePath, "go.work")
 	modulePath := "forge.lthn.ai/core/" + repo
 
 	workData, err := coreio.Local.Read(goWorkPath)
@@ -683,19 +702,19 @@ func (s *PrepSubsystem) findConsumers(repo, wsDir string) int {
 	}
 
 	var consumers []string
-	for _, line := range strings.Split(workData, "\n") {
-		line = strings.TrimSpace(line)
-		if !strings.HasPrefix(line, "./") {
+	for _, line := range core.Split(workData, "\n") {
+		line = core.Trim(line)
+		if !core.HasPrefix(line, "./") {
 			continue
 		}
-		dir := filepath.Join(s.codePath, strings.TrimPrefix(line, "./"))
-		goMod := filepath.Join(dir, "go.mod")
+		dir := core.Path(s.codePath, core.TrimPrefix(line, "./"))
+		goMod := core.Path(dir, "go.mod")
 		modData, err := coreio.Local.Read(goMod)
 		if err != nil {
 			continue
 		}
-		if strings.Contains(modData, modulePath) && !strings.HasPrefix(modData, "module "+modulePath) {
-			consumers = append(consumers, filepath.Base(dir))
+		if core.Contains(modData, modulePath) && !core.HasPrefix(modData, "module "+modulePath) {
+			consumers = append(consumers, core.PathBase(dir))
 		}
 	}
 
@@ -705,8 +724,8 @@ func (s *PrepSubsystem) findConsumers(repo, wsDir string) int {
 		for _, c := range consumers {
 			content += "- " + c + "\n"
 		}
-		content += fmt.Sprintf("\n**Breaking change risk: %d consumers.**\n", len(consumers))
-		_ = writeAtomic(filepath.Join(wsDir, "src", "CONSUMERS.md"), content)
+		content += core.Sprintf("\n**Breaking change risk: %d consumers.**\n", len(consumers))
+		_ = writeAtomic(core.Path(wsDir, "src", "CONSUMERS.md"), content)
 	}
 
 	return len(consumers)
@@ -720,10 +739,10 @@ func (s *PrepSubsystem) gitLog(repoPath, wsDir string) int {
 		return 0
 	}
 
-	lines := strings.Split(strings.TrimSpace(string(output)), "\n")
+	lines := core.Split(core.Trim(string(output)), "\n")
 	if len(lines) > 0 && lines[0] != "" {
 		content := "# Recent Changes\n\n```\n" + string(output) + "```\n"
-		_ = writeAtomic(filepath.Join(wsDir, "src", "RECENT.md"), content)
+		_ = writeAtomic(core.Path(wsDir, "src", "RECENT.md"), content)
 	}
 
 	return len(lines)
@@ -734,7 +753,7 @@ func (s *PrepSubsystem) generateTodo(ctx context.Context, org, repo string, issu
 		return
 	}
 
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/issues/%d", s.forgeURL, org, repo, issue)
+	url := core.Sprintf("%s/api/v1/repos/%s/%s/issues/%d", s.forgeURL, org, repo, issue)
 	req, _ := http.NewRequestWithContext(ctx, "GET", url, nil)
 	req.Header.Set("Authorization", "token "+s.forgeToken)
 
@@ -753,11 +772,11 @@ func (s *PrepSubsystem) generateTodo(ctx context.Context, org, repo string, issu
 	}
 	json.NewDecoder(resp.Body).Decode(&issueData)
 
-	content := fmt.Sprintf("# TASK: %s\n\n", issueData.Title)
-	content += fmt.Sprintf("**Status:** ready\n")
-	content += fmt.Sprintf("**Source:** %s/%s/%s/issues/%d\n", s.forgeURL, org, repo, issue)
-	content += fmt.Sprintf("**Repo:** %s/%s\n\n---\n\n", org, repo)
+	content := core.Sprintf("# TASK: %s\n\n", issueData.Title)
+	content += core.Sprintf("**Status:** ready\n")
+	content += core.Sprintf("**Source:** %s/%s/%s/issues/%d\n", s.forgeURL, org, repo, issue)
+	content += core.Sprintf("**Repo:** %s/%s\n\n---\n\n", org, repo)
 	content += "## Objective\n\n" + issueData.Body + "\n"
 
-	_ = writeAtomic(filepath.Join(wsDir, "src", "TODO.md"), content)
+	_ = writeAtomic(core.Path(wsDir, "src", "TODO.md"), content)
 }
diff --git a/pkg/mcp/agentic/queue.go b/pkg/mcp/agentic/queue.go
index ff5fe1a..a02c7b9 100644
--- a/pkg/mcp/agentic/queue.go
+++ b/pkg/mcp/agentic/queue.go
@@ -3,18 +3,19 @@
 package agentic
 
 import (
-	"fmt"
 	"os"
 	"os/exec"
-	"path/filepath"
-	"strings"
 	"syscall"
 	"time"
 
+	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
 	"gopkg.in/yaml.v3"
 )
 
+// os.Create, os.Open, os.DevNull, os.Environ, os.FindProcess are used for
+// process spawning and management — no core equivalents for these OS primitives.
+
 // DispatchConfig controls agent dispatch behaviour.
 type DispatchConfig struct {
 	DefaultAgent    string `yaml:"default_agent"`
@@ -43,7 +44,7 @@ type AgentsConfig struct {
 // loadAgentsConfig reads config/agents.yaml from the code path.
 func (s *PrepSubsystem) loadAgentsConfig() *AgentsConfig {
 	paths := []string{
-		filepath.Join(s.codePath, ".core", "agents.yaml"),
+		core.Path(s.codePath, ".core", "agents.yaml"),
 	}
 
 	for _, path := range paths {
@@ -79,9 +80,16 @@ func (s *PrepSubsystem) delayForAgent(agent string) time.Duration {
 		return 0
 	}
 
-	// Parse reset time
+	// Parse reset time (format: "HH:MM")
 	resetHour, resetMin := 6, 0
-	fmt.Sscanf(rate.ResetUTC, "%d:%d", &resetHour, &resetMin)
+	if parts := core.Split(rate.ResetUTC, ":"); len(parts) == 2 {
+		if h, ok := parseSimpleInt(parts[0]); ok {
+			resetHour = h
+		}
+		if m, ok := parseSimpleInt(parts[1]); ok {
+			resetMin = m
+		}
+	}
 
 	now := time.Now().UTC()
 	resetToday := time.Date(now.Year(), now.Month(), now.Day(), resetHour, resetMin, 0, 0, time.UTC)
@@ -115,9 +123,9 @@ func (s *PrepSubsystem) listWorkspaceDirs() []string {
 		if !entry.IsDir() {
 			continue
 		}
-		path := filepath.Join(wsRoot, entry.Name())
+		path := core.Path(wsRoot, entry.Name())
 		// Check if this dir has a status.json (it's a workspace)
-		if coreio.Local.IsFile(filepath.Join(path, "status.json")) {
+		if coreio.Local.IsFile(core.Path(path, "status.json")) {
 			dirs = append(dirs, path)
 			continue
 		}
@@ -128,8 +136,8 @@ func (s *PrepSubsystem) listWorkspaceDirs() []string {
 		}
 		for _, sub := range subEntries {
 			if sub.IsDir() {
-				subPath := filepath.Join(path, sub.Name())
-				if coreio.Local.IsFile(filepath.Join(subPath, "status.json")) {
+				subPath := core.Path(path, sub.Name())
+				if coreio.Local.IsFile(core.Path(subPath, "status.json")) {
 					dirs = append(dirs, subPath)
 				}
 			}
@@ -146,7 +154,7 @@ func (s *PrepSubsystem) countRunningByAgent(agent string) int {
 		if err != nil || st.Status != "running" {
 			continue
 		}
-		stBase := strings.SplitN(st.Agent, ":", 2)[0]
+		stBase := core.SplitN(st.Agent, ":", 2)[0]
 		if stBase != agent {
 			continue
 		}
@@ -162,7 +170,7 @@ func (s *PrepSubsystem) countRunningByAgent(agent string) int {
 
 // baseAgent strips the model variant (gemini:flash → gemini).
 func baseAgent(agent string) string {
-	return strings.SplitN(agent, ":", 2)[0]
+	return core.SplitN(agent, ":", 2)[0]
 }
 
 // canDispatchAgent checks if we're under the concurrency limit for a specific agent type.
@@ -176,6 +184,23 @@ func (s *PrepSubsystem) canDispatchAgent(agent string) bool {
 	return s.countRunningByAgent(base) < limit
 }
 
+// parseSimpleInt parses a small non-negative integer from a string.
+// Returns (value, true) on success, (0, false) on failure.
+func parseSimpleInt(s string) (int, bool) {
+	s = core.Trim(s)
+	if s == "" {
+		return 0, false
+	}
+	n := 0
+	for _, r := range s {
+		if r < '0' || r > '9' {
+			return 0, false
+		}
+		n = n*10 + int(r-'0')
+	}
+	return n, true
+}
+
 // canDispatch is kept for backwards compat.
 func (s *PrepSubsystem) canDispatch() bool {
 	return true
@@ -205,7 +230,7 @@ func (s *PrepSubsystem) drainQueue() {
 			continue
 		}
 
-		srcDir := filepath.Join(wsDir, "src")
+		srcDir := core.Path(wsDir, "src")
 		prompt := "Read PROMPT.md for instructions. All context files (CLAUDE.md, TODO.md, CONTEXT.md, CONSUMERS.md, RECENT.md) are in the parent directory. Work in this directory."
 
 		command, args, err := agentCommand(st.Agent, prompt)
@@ -213,7 +238,7 @@ func (s *PrepSubsystem) drainQueue() {
 			continue
 		}
 
-		outputFile := filepath.Join(wsDir, fmt.Sprintf("agent-%s.log", st.Agent))
+		outputFile := core.Path(wsDir, core.Sprintf("agent-%s.log", st.Agent))
 		outFile, err := os.Create(outputFile)
 		if err != nil {
 			continue
diff --git a/pkg/mcp/agentic/repo_helpers.go b/pkg/mcp/agentic/repo_helpers.go
index d50c1b8..cb03de0 100644
--- a/pkg/mcp/agentic/repo_helpers.go
+++ b/pkg/mcp/agentic/repo_helpers.go
@@ -5,19 +5,18 @@ package agentic
 import (
 	"context"
 	"encoding/json"
-	"os"
 	"os/exec"
-	"path/filepath"
 	"regexp"
 	"strconv"
-	"strings"
 	"time"
 
+	core "dappco.re/go/core"
+	coreio "dappco.re/go/core/io"
 	coreerr "dappco.re/go/core/log"
 )
 
 func listLocalRepos(basePath string) []string {
-	entries, err := os.ReadDir(basePath)
+	entries, err := coreio.Local.List(basePath)
 	if err != nil {
 		return nil
 	}
@@ -35,7 +34,7 @@ func hasRemote(repoDir, remote string) bool {
 	cmd := exec.Command("git", "remote", "get-url", remote)
 	cmd.Dir = repoDir
 	if out, err := cmd.Output(); err == nil {
-		return strings.TrimSpace(string(out)) != ""
+		return core.Trim(string(out)) != ""
 	}
 	return false
 }
@@ -48,7 +47,7 @@ func commitsAhead(repoDir, baseRef, headRef string) int {
 		return 0
 	}
 
-	count, err := parsePositiveInt(strings.TrimSpace(string(out)))
+	count, err := parsePositiveInt(core.Trim(string(out)))
 	if err != nil {
 		return 0
 	}
@@ -64,8 +63,8 @@ func filesChanged(repoDir, baseRef, headRef string) int {
 	}
 
 	count := 0
-	for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n") {
-		if strings.TrimSpace(line) != "" {
+	for _, line := range core.Split(core.Trim(string(out)), "\n") {
+		if core.Trim(line) != "" {
 			count++
 		}
 	}
@@ -79,11 +78,11 @@ func gitOutput(repoDir string, args ...string) (string, error) {
 	if err != nil {
 		return "", coreerr.E("gitOutput", string(out), err)
 	}
-	return strings.TrimSpace(string(out)), nil
+	return core.Trim(string(out)), nil
 }
 
 func parsePositiveInt(value string) (int, error) {
-	value = strings.TrimSpace(value)
+	value = core.Trim(value)
 	if value == "" {
 		return 0, coreerr.E("parsePositiveInt", "empty value", nil)
 	}
@@ -148,11 +147,11 @@ func createGitHubPR(ctx context.Context, repoDir, repo string, commits, files in
 		return "", coreerr.E("createGitHubPR", string(out), err)
 	}
 
-	lines := strings.Split(strings.TrimSpace(string(out)), "\n")
+	lines := core.Split(core.Trim(string(out)), "\n")
 	if len(lines) == 0 {
 		return "", nil
 	}
-	return strings.TrimSpace(lines[len(lines)-1]), nil
+	return core.Trim(lines[len(lines)-1]), nil
 }
 
 func ensureDevBranch(repoDir string) error {
@@ -194,7 +193,7 @@ func parseRetryAfter(detail string) time.Duration {
 		return 5 * time.Minute
 	}
 
-	switch strings.ToLower(match[2]) {
+	switch core.Lower(match[2]) {
 	case "hour", "hours":
 		return time.Duration(n) * time.Hour
 	case "second", "seconds":
@@ -205,5 +204,5 @@ func parseRetryAfter(detail string) time.Duration {
 }
 
 func repoRootFromCodePath(codePath string) string {
-	return filepath.Join(codePath, "core")
+	return core.Path(codePath, "core")
 }
diff --git a/pkg/mcp/agentic/resume.go b/pkg/mcp/agentic/resume.go
index 8528da6..ac5160f 100644
--- a/pkg/mcp/agentic/resume.go
+++ b/pkg/mcp/agentic/resume.go
@@ -4,16 +4,14 @@ package agentic
 
 import (
 	"context"
-	"fmt"
 	"os"
 	"os/exec"
-	"path/filepath"
-	"strings"
 	"syscall"
 
-	coremcp "dappco.re/go/mcp/pkg/mcp"
+	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
 	coreerr "dappco.re/go/core/log"
+	coremcp "dappco.re/go/mcp/pkg/mcp"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
@@ -52,8 +50,8 @@ func (s *PrepSubsystem) resume(ctx context.Context, _ *mcp.CallToolRequest, inpu
 		return nil, ResumeOutput{}, coreerr.E("resume", "workspace is required", nil)
 	}
 
-	wsDir := filepath.Join(s.workspaceRoot(), input.Workspace)
-	srcDir := filepath.Join(wsDir, "src")
+	wsDir := core.Path(s.workspaceRoot(), input.Workspace)
+	srcDir := core.Path(wsDir, "src")
 
 	// Verify workspace exists
 	if _, err := coreio.Local.List(srcDir); err != nil {
@@ -78,8 +76,8 @@ func (s *PrepSubsystem) resume(ctx context.Context, _ *mcp.CallToolRequest, inpu
 
 	// Write ANSWER.md if answer provided
 	if input.Answer != "" {
-		answerPath := filepath.Join(srcDir, "ANSWER.md")
-		content := fmt.Sprintf("# Answer\n\n%s\n", input.Answer)
+		answerPath := core.Path(srcDir, "ANSWER.md")
+		content := core.Sprintf("# Answer\n\n%s\n", input.Answer)
 		if err := writeAtomic(answerPath, content); err != nil {
 			return nil, ResumeOutput{}, coreerr.E("resume", "failed to write ANSWER.md", err)
 		}
@@ -102,7 +100,7 @@ func (s *PrepSubsystem) resume(ctx context.Context, _ *mcp.CallToolRequest, inpu
 	}
 
 	// Spawn agent as detached process (survives parent death)
-	outputFile := filepath.Join(wsDir, fmt.Sprintf("agent-%s-run%d.log", agent, st.Runs+1))
+	outputFile := core.Path(wsDir, core.Sprintf("agent-%s-run%d.log", agent, st.Runs+1))
 
 	command, args, err := agentCommand(agent, prompt)
 	if err != nil {
@@ -154,10 +152,10 @@ func (s *PrepSubsystem) resume(ctx context.Context, _ *mcp.CallToolRequest, inpu
 			"branch":    st.Branch,
 		}
 
-		if data, err := coreio.Local.Read(filepath.Join(srcDir, "BLOCKED.md")); err == nil {
+		if data, err := coreio.Local.Read(core.Path(srcDir, "BLOCKED.md")); err == nil {
 			status = "blocked"
 			channel = coremcp.ChannelAgentBlocked
-			st.Question = strings.TrimSpace(data)
+			st.Question = core.Trim(data)
 			if st.Question != "" {
 				payload["question"] = st.Question
 			}
diff --git a/pkg/mcp/agentic/review_queue.go b/pkg/mcp/agentic/review_queue.go
index df8c354..050df04 100644
--- a/pkg/mcp/agentic/review_queue.go
+++ b/pkg/mcp/agentic/review_queue.go
@@ -5,16 +5,14 @@ package agentic
 import (
 	"context"
 	"encoding/json"
-	"fmt"
 	"os"
 	"os/exec"
-	"path/filepath"
 	"regexp"
-	"strings"
 	"time"
 
-	coremcp "dappco.re/go/mcp/pkg/mcp"
+	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
+	coremcp "dappco.re/go/mcp/pkg/mcp"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
@@ -93,7 +91,7 @@ func (s *PrepSubsystem) reviewQueue(ctx context.Context, _ *mcp.CallToolRequest,
 			continue
 		}
 
-		repoDir := filepath.Join(basePath, repo)
+		repoDir := core.Path(basePath, repo)
 		reviewer := input.Reviewer
 		if reviewer == "" {
 			reviewer = "coderabbit"
@@ -137,7 +135,7 @@ func (s *PrepSubsystem) findReviewCandidates(basePath string) []string {
 		if !entry.IsDir() {
 			continue
 		}
-		repoDir := filepath.Join(basePath, entry.Name())
+		repoDir := core.Path(basePath, entry.Name())
 		if !hasRemote(repoDir, "github") {
 			continue
 		}
@@ -154,22 +152,22 @@ func (s *PrepSubsystem) reviewRepo(ctx context.Context, repoDir, repo, reviewer
 
 	if rl := s.loadRateLimitState(); rl != nil && rl.Limited && time.Now().Before(rl.RetryAt) {
 		result.Verdict = "rate_limited"
-		result.Detail = fmt.Sprintf("retry after %s", rl.RetryAt.Format(time.RFC3339))
+		result.Detail = core.Sprintf("retry after %s", rl.RetryAt.Format(time.RFC3339))
 		return result
 	}
 
 	cmd := reviewerCommand(ctx, repoDir, reviewer)
 	cmd.Dir = repoDir
 	out, err := cmd.CombinedOutput()
-	output := strings.TrimSpace(string(out))
+	output := core.Trim(string(out))
 
-	if strings.Contains(strings.ToLower(output), "rate limit") {
+	if core.Contains(core.Lower(output), "rate limit") {
 		result.Verdict = "rate_limited"
 		result.Detail = output
 		return result
 	}
 
-	if err != nil && !strings.Contains(output, "No findings") && !strings.Contains(output, "no issues") {
+	if err != nil && !core.Contains(output, "No findings") && !core.Contains(output, "no issues") {
 		result.Verdict = "error"
 		if output != "" {
 			result.Detail = output
@@ -182,7 +180,7 @@ func (s *PrepSubsystem) reviewRepo(ctx context.Context, repoDir, repo, reviewer
 	s.storeReviewOutput(repoDir, repo, reviewer, output)
 	result.Findings = countFindingHints(output)
 
-	if strings.Contains(output, "No findings") || strings.Contains(output, "no issues") || strings.Contains(output, "LGTM") {
+	if core.Contains(output, "No findings") || core.Contains(output, "no issues") || core.Contains(output, "LGTM") {
 		result.Verdict = "clean"
 		if dryRun {
 			result.Action = "skipped (dry run)"
@@ -198,7 +196,7 @@ func (s *PrepSubsystem) reviewRepo(ctx context.Context, repoDir, repo, reviewer
 			mergeCmd.Dir = repoDir
 			if mergeOut, err := mergeCmd.CombinedOutput(); err == nil {
 				result.Action = "merged"
-				result.Detail = strings.TrimSpace(string(mergeOut))
+				result.Detail = core.Trim(string(mergeOut))
 				return result
 			}
 		}
@@ -219,7 +217,7 @@ func (s *PrepSubsystem) reviewRepo(ctx context.Context, repoDir, repo, reviewer
 
 func (s *PrepSubsystem) storeReviewOutput(repoDir, repo, reviewer, output string) {
 	home := reviewQueueHomeDir()
-	dataDir := filepath.Join(home, ".core", "training", "reviews")
+	dataDir := core.Path(home, ".core", "training", "reviews")
 	if err := coreio.Local.EnsureDir(dataDir); err != nil {
 		return
 	}
@@ -235,13 +233,13 @@ func (s *PrepSubsystem) storeReviewOutput(repoDir, repo, reviewer, output string
 		return
 	}
 
-	name := fmt.Sprintf("%s-%s-%d.json", repo, reviewer, time.Now().Unix())
-	_ = writeAtomic(filepath.Join(dataDir, name), string(data))
+	name := core.Sprintf("%s-%s-%d.json", repo, reviewer, time.Now().Unix())
+	_ = writeAtomic(core.Path(dataDir, name), string(data))
 }
 
 func (s *PrepSubsystem) saveRateLimitState(info *RateLimitInfo) {
 	home := reviewQueueHomeDir()
-	path := filepath.Join(home, ".core", "coderabbit-ratelimit.json")
+	path := core.Path(home, ".core", "coderabbit-ratelimit.json")
 	data, err := json.Marshal(info)
 	if err != nil {
 		return
@@ -251,7 +249,7 @@ func (s *PrepSubsystem) saveRateLimitState(info *RateLimitInfo) {
 
 func (s *PrepSubsystem) loadRateLimitState() *RateLimitInfo {
 	home := reviewQueueHomeDir()
-	path := filepath.Join(home, ".core", "coderabbit-ratelimit.json")
+	path := core.Path(home, ".core", "coderabbit-ratelimit.json")
 	data, err := coreio.Local.Read(path)
 	if err != nil {
 		return nil
diff --git a/pkg/mcp/agentic/scan.go b/pkg/mcp/agentic/scan.go
index 564962f..7e40f47 100644
--- a/pkg/mcp/agentic/scan.go
+++ b/pkg/mcp/agentic/scan.go
@@ -6,7 +6,6 @@ import (
 	"context"
 	"encoding/json"
 	"net/http"
-	"strings"
 
 	core "dappco.re/go/core"
 	coreerr "dappco.re/go/core/log"
@@ -170,7 +169,7 @@ func (s *PrepSubsystem) listRepoIssues(ctx context.Context, org, repo, label str
 			Title:    issue.Title,
 			Labels:   labels,
 			Assignee: assignee,
-			URL:      strings.Replace(issue.HTMLURL, "https://forge.lthn.ai", s.forgeURL, 1),
+			URL:      core.Replace(issue.HTMLURL, "https://forge.lthn.ai", s.forgeURL),
 		})
 	}
 
diff --git a/pkg/mcp/agentic/status.go b/pkg/mcp/agentic/status.go
index 4f3b28b..d789ece 100644
--- a/pkg/mcp/agentic/status.go
+++ b/pkg/mcp/agentic/status.go
@@ -15,6 +15,9 @@ import (
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
+// os.Stat and os.FindProcess are used for workspace age detection and PID
+// liveness checks — these are OS-level queries with no core equivalent.
+
 // Workspace status file convention:
 //
 //   {workspace}/status.json  — current state of the workspace
diff --git a/pkg/mcp/agentic/write_atomic.go b/pkg/mcp/agentic/write_atomic.go
index 72bb9a7..8f46118 100644
--- a/pkg/mcp/agentic/write_atomic.go
+++ b/pkg/mcp/agentic/write_atomic.go
@@ -9,6 +9,9 @@ import (
 	coreio "dappco.re/go/core/io"
 )
 
+// os.CreateTemp, os.Remove, os.Rename are framework-boundary calls for
+// atomic file writes — no core equivalent exists for temp file creation.
+
 // writeAtomic writes content to path by staging it in a temporary file and
 // renaming it into place.
 //
diff --git a/pkg/mcp/brain/direct.go b/pkg/mcp/brain/direct.go
index acfb829..cb59d3a 100644
--- a/pkg/mcp/brain/direct.go
+++ b/pkg/mcp/brain/direct.go
@@ -3,20 +3,15 @@
 package brain
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"fmt"
-	goio "io"
 	"net/http"
 	"net/url"
-	"os"
-	"strings"
 	"time"
 
-	coremcp "dappco.re/go/mcp/pkg/mcp"
+	core "dappco.re/go/core"
 	coreio "dappco.re/go/core/io"
 	coreerr "dappco.re/go/core/log"
+	coremcp "dappco.re/go/mcp/pkg/mcp"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
 )
 
@@ -58,15 +53,16 @@ func (s *DirectSubsystem) OnChannel(fn func(ctx context.Context, channel string,
 // Reads CORE_BRAIN_URL and CORE_BRAIN_KEY from environment, or falls back
 // to ~/.claude/brain.key for the API key.
 func NewDirect() *DirectSubsystem {
-	apiURL := os.Getenv("CORE_BRAIN_URL")
+	apiURL := core.Env("CORE_BRAIN_URL")
 	if apiURL == "" {
 		apiURL = "https://api.lthn.sh"
 	}
 
-	apiKey := os.Getenv("CORE_BRAIN_KEY")
+	apiKey := core.Env("CORE_BRAIN_KEY")
 	if apiKey == "" {
-		if data, err := coreio.Local.Read(os.ExpandEnv("$HOME/.claude/brain.key")); err == nil {
-			apiKey = strings.TrimSpace(data)
+		home := core.Env("HOME")
+		if data, err := coreio.Local.Read(core.Path(home, ".claude", "brain.key")); err == nil {
+			apiKey = core.Trim(data)
 		}
 	}
 
@@ -112,16 +108,12 @@ func (s *DirectSubsystem) apiCall(ctx context.Context, method, path string, body
 		return nil, coreerr.E("brain.apiCall", "no API key (set CORE_BRAIN_KEY or create ~/.claude/brain.key)", nil)
 	}
 
-	var reqBody goio.Reader
+	var bodyStr string
 	if body != nil {
-		data, err := json.Marshal(body)
-		if err != nil {
-			return nil, coreerr.E("brain.apiCall", "marshal request", err)
-		}
-		reqBody = bytes.NewReader(data)
+		bodyStr = core.JSONMarshalString(body)
 	}
 
-	req, err := http.NewRequestWithContext(ctx, method, s.apiURL+path, reqBody)
+	req, err := http.NewRequestWithContext(ctx, method, s.apiURL+path, core.NewReader(bodyStr))
 	if err != nil {
 		return nil, coreerr.E("brain.apiCall", "create request", err)
 	}
@@ -135,18 +127,22 @@ func (s *DirectSubsystem) apiCall(ctx context.Context, method, path string, body
 	}
 	defer resp.Body.Close()
 
-	respData, err := goio.ReadAll(resp.Body)
-	if err != nil {
-		return nil, coreerr.E("brain.apiCall", "read response", err)
+	r := core.ReadAll(resp.Body)
+	if !r.OK {
+		if readErr, ok := r.Value.(error); ok {
+			return nil, coreerr.E("brain.apiCall", "read response", readErr)
+		}
+		return nil, coreerr.E("brain.apiCall", "read response failed", nil)
 	}
+	respData := r.Value.(string)
 
 	if resp.StatusCode >= 400 {
-		return nil, coreerr.E("brain.apiCall", "API returned "+string(respData), nil)
+		return nil, coreerr.E("brain.apiCall", "API returned "+respData, nil)
 	}
 
 	var result map[string]any
-	if err := json.Unmarshal(respData, &result); err != nil {
-		return nil, coreerr.E("brain.apiCall", "parse response", err)
+	if ur := core.JSONUnmarshal([]byte(respData), &result); !ur.OK {
+		return nil, coreerr.E("brain.apiCall", "parse response", nil)
 	}
 
 	return result, nil
@@ -200,30 +196,7 @@ func (s *DirectSubsystem) recall(ctx context.Context, _ *mcp.CallToolRequest, in
 		return nil, RecallOutput{}, err
 	}
 
-	var memories []Memory
-	if mems, ok := result["memories"].([]any); ok {
-		for _, m := range mems {
-			if mm, ok := m.(map[string]any); ok {
-				mem := Memory{
-					Content:   fmt.Sprintf("%v", mm["content"]),
-					Type:      fmt.Sprintf("%v", mm["type"]),
-					Project:   fmt.Sprintf("%v", mm["project"]),
-					AgentID:   fmt.Sprintf("%v", mm["agent_id"]),
-					CreatedAt: fmt.Sprintf("%v", mm["created_at"]),
-				}
-				if id, ok := mm["id"].(string); ok {
-					mem.ID = id
-				}
-				if score, ok := mm["score"].(float64); ok {
-					mem.Confidence = score
-				}
-				if source, ok := mm["source"].(string); ok {
-					mem.Tags = append(mem.Tags, "source:"+source)
-				}
-				memories = append(memories, mem)
-			}
-		}
-	}
+	memories := memoriesFromResult(result)
 
 	if s.onChannel != nil {
 		s.onChannel(ctx, coremcp.ChannelBrainRecallDone, map[string]any{
@@ -274,37 +247,14 @@ func (s *DirectSubsystem) list(ctx context.Context, _ *mcp.CallToolRequest, inpu
 	if input.AgentID != "" {
 		values.Set("agent_id", input.AgentID)
 	}
-	values.Set("limit", fmt.Sprintf("%d", limit))
+	values.Set("limit", core.Sprintf("%d", limit))
 
 	result, err := s.apiCall(ctx, http.MethodGet, "/v1/brain/list?"+values.Encode(), nil)
 	if err != nil {
 		return nil, ListOutput{}, err
 	}
 
-	var memories []Memory
-	if mems, ok := result["memories"].([]any); ok {
-		for _, m := range mems {
-			if mm, ok := m.(map[string]any); ok {
-				mem := Memory{
-					Content:   fmt.Sprintf("%v", mm["content"]),
-					Type:      fmt.Sprintf("%v", mm["type"]),
-					Project:   fmt.Sprintf("%v", mm["project"]),
-					AgentID:   fmt.Sprintf("%v", mm["agent_id"]),
-					CreatedAt: fmt.Sprintf("%v", mm["created_at"]),
-				}
-				if id, ok := mm["id"].(string); ok {
-					mem.ID = id
-				}
-				if score, ok := mm["score"].(float64); ok {
-					mem.Confidence = score
-				}
-				if source, ok := mm["source"].(string); ok {
-					mem.Tags = append(mem.Tags, "source:"+source)
-				}
-				memories = append(memories, mem)
-			}
-		}
-	}
+	memories := memoriesFromResult(result)
 
 	if s.onChannel != nil {
 		s.onChannel(ctx, coremcp.ChannelBrainListDone, map[string]any{
@@ -321,3 +271,49 @@ func (s *DirectSubsystem) list(ctx context.Context, _ *mcp.CallToolRequest, inpu
 		Memories: memories,
 	}, nil
 }
+
+// memoriesFromResult extracts Memory entries from an API response map.
+func memoriesFromResult(result map[string]any) []Memory {
+	var memories []Memory
+	mems, ok := result["memories"].([]any)
+	if !ok {
+		return memories
+	}
+	for _, m := range mems {
+		mm, ok := m.(map[string]any)
+		if !ok {
+			continue
+		}
+		mem := Memory{
+			Content:   stringFromMap(mm, "content"),
+			Type:      stringFromMap(mm, "type"),
+			Project:   stringFromMap(mm, "project"),
+			AgentID:   stringFromMap(mm, "agent_id"),
+			CreatedAt: stringFromMap(mm, "created_at"),
+		}
+		if id, ok := mm["id"].(string); ok {
+			mem.ID = id
+		}
+		if score, ok := mm["score"].(float64); ok {
+			mem.Confidence = score
+		}
+		if source, ok := mm["source"].(string); ok {
+			mem.Tags = append(mem.Tags, "source:"+source)
+		}
+		memories = append(memories, mem)
+	}
+	return memories
+}
+
+// stringFromMap extracts a string value from a map, returning "" if missing or wrong type.
+func stringFromMap(m map[string]any, key string) string {
+	v, ok := m[key]
+	if !ok || v == nil {
+		return ""
+	}
+	s, ok := v.(string)
+	if !ok {
+		return core.Sprintf("%v", v)
+	}
+	return s
+}
diff --git a/pkg/mcp/mcp.go b/pkg/mcp/mcp.go
index fb2ff83..dafed1d 100644
--- a/pkg/mcp/mcp.go
+++ b/pkg/mcp/mcp.go
@@ -5,13 +5,13 @@
 package mcp
 
 import (
+	"cmp"
 	"context"
 	"iter"
 	"net/http"
 	"os"
 	"path/filepath"
 	"slices"
-	"sort"
 	"sync"
 
 	core "dappco.re/go/core"
@@ -542,8 +542,8 @@ func (s *Service) listDirectory(ctx context.Context, req *mcp.CallToolRequest, i
 	if err != nil {
 		return nil, ListDirectoryOutput{}, log.E("mcp.listDirectory", "failed to list directory", err)
 	}
-	sort.Slice(entries, func(i, j int) bool {
-		return entries[i].Name() < entries[j].Name()
+	slices.SortFunc(entries, func(a, b os.DirEntry) int {
+		return cmp.Compare(a.Name(), b.Name())
 	})
 	result := make([]DirectoryEntry, 0, len(entries))
 	for _, e := range entries {
diff --git a/pkg/mcp/notify.go b/pkg/mcp/notify.go
index 78275ba..17c9eeb 100644
--- a/pkg/mcp/notify.go
+++ b/pkg/mcp/notify.go
@@ -7,13 +7,13 @@
 package mcp
 
 import (
+	"cmp"
 	"context"
 	"io"
 	"iter"
 	"os"
 	"reflect"
 	"slices"
-	"sort"
 	"sync"
 	"unsafe"
 
@@ -362,8 +362,8 @@ func snapshotSessions(server *mcp.Server) []*mcp.ServerSession {
 		}
 	}
 
-	sort.Slice(sessions, func(i, j int) bool {
-		return sessions[i].ID() < sessions[j].ID()
+	slices.SortFunc(sessions, func(a, b *mcp.ServerSession) int {
+		return cmp.Compare(a.ID(), b.ID())
 	})
 
 	return sessions
diff --git a/pkg/mcp/process_notifications.go b/pkg/mcp/process_notifications.go
index 19c2679..1f2daf4 100644
--- a/pkg/mcp/process_notifications.go
+++ b/pkg/mcp/process_notifications.go
@@ -4,7 +4,6 @@ package mcp
 
 import (
 	"context"
-	"strings"
 	"time"
 
 	core "dappco.re/go/core"
@@ -58,12 +57,13 @@ func isTestProcess(command string, args []string) bool {
 
 	switch base {
 	case "go":
-		return len(args) > 0 && strings.EqualFold(args[0], "test")
+		return len(args) > 0 && core.Lower(args[0]) == "test"
 	case "cargo":
-		return len(args) > 0 && strings.EqualFold(args[0], "test")
+		return len(args) > 0 && core.Lower(args[0]) == "test"
 	case "npm", "pnpm", "yarn", "bun":
 		for _, arg := range args {
-			if strings.EqualFold(arg, "test") || core.HasPrefix(core.Lower(arg), "test:") {
+			lower := core.Lower(arg)
+			if lower == "test" || core.HasPrefix(lower, "test:") {
 				return true
 			}
 		}
diff --git a/pkg/mcp/transport_http.go b/pkg/mcp/transport_http.go
index 9a2e4b0..49a5a11 100644
--- a/pkg/mcp/transport_http.go
+++ b/pkg/mcp/transport_http.go
@@ -7,7 +7,6 @@ import (
 	"crypto/subtle"
 	"net"
 	"net/http"
-	"os"
 	"time"
 
 	core "dappco.re/go/core"
@@ -37,7 +36,7 @@ func (s *Service) ServeHTTP(ctx context.Context, addr string) error {
 		addr = DefaultHTTPAddr
 	}
 
-	authToken := os.Getenv("MCP_AUTH_TOKEN")
+	authToken := core.Env("MCP_AUTH_TOKEN")
 
 	handler := mcp.NewStreamableHTTPHandler(
 		func(r *http.Request) *mcp.Server {