[log] Add debug logging to IsSingularReadTool in tool_policy.go

[github-actions]

Summary

Adds debug logging to internal/server/tool_policy.go, following the project's logging guidelines from AGENTS.md.

Changes

• Added a new logToolPolicy logger (server:tool_policy namespace via logger.ForFile()).
• Added a debug log call in IsSingularReadTool reporting the tool name and the collection/singular classification decision, guarded by logToolPolicy.Enabled() to avoid unnecessary computation when debug logging is disabled.

This file previously had no logger and no debug visibility into how the DIFC filtering layer classifies GitHub MCP tool calls as singular-read vs. collection tools — a decision that directly affects response filtering behavior.

Validation

• go build ./... — succeeds
• go vet ./internal/server/... — clean
• go test ./internal/server/... — all tests pass
• Built the awmg binary successfully with the change included

Only this one file was modified; no test files or unrelated code were touched.

Generated by Go Logger Enhancement · auto · 103.9 AIC · ⊞ 12.4K · ◷

[Copilot]

Pull request overview

Adds debug visibility into singular-versus-collection tool classification.

Changes:

• Adds a file-derived server:tool_policy logger.
• Logs classification decisions when debug logging is enabled.

Show a summary per file

File	Description
internal/server/tool_policy.go	Adds guarded debug logging without changing classification behavior.

Review details

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• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Balanced

[github-actions]

🔒 mcpg Read-Only Stress — default AWF

Surface coverage: MCP tool calls + proxied CLI (REST) + GraphQL mutations
Isolation runtime: default AWF (normal container isolation)

Gateway tool inventory: 22 read-only tools exposed; all write tools absent at gateway level.

Part	Surface	Op	Result	Expected	Status
A	MCP	reads (list_issues, list_pull_requests, get_file_contents, list_commits)	data returned	ALLOWED	✅
B	MCP	writes (reaction/star/issue/comment/branch/file/PR)	Error [-32602]: unknown tool	BLOCKED	✅
C	CLI	reads (list_issues, get_file_contents)	data returned	ALLOWED	✅
D	CLI	REST writes (reaction/star/issue/comment/file)	gh: no GH_TOKEN set	BLOCKED	✅
E	CLI	GraphQL mutations (addReaction/addStar/createIssue)	gh: no GH_TOKEN set	BLOCKED	✅

Overall: PASS

Note on Part B enforcement: The gateway exposes only 22 read-only tools. Write tool calls return Error [-32602]: unknown tool — gateway-level enforcement (filtered tool registry), not merely backend config.

Note on Parts D/E: gh CLI is unauthenticated (no GH_TOKEN). The security boundary is: mcpg (read-only MCP) + unauthenticated gh.

References: §30961042701

🔒 mcpg read-only stress (default AWF runtime) by Read-Only Stress: default runtime

[github-actions]

🔒 mcpg Read-Only Stress — docker-sbx

Surface coverage: MCP tool calls + proxied CLI (REST) + GraphQL mutations
Isolation runtime: docker-sbx (KVM-isolated microVM)

Part	Surface	Op	Result	Expected	Status
A	MCP	reads (issues/PRs/file/commits)	data returned	ALLOWED	✅
B	MCP	writes (reaction/star/issue/comment/branch/file/PR)	Error[-32602] unknown tool	BLOCKED	✅
C	CLI	reads (list issues via github CLI)	data returned	ALLOWED	✅
D	CLI	REST writes (reaction/star/issue/comment/file)	refused (no GH_TOKEN)	BLOCKED	✅
E	CLI	GraphQL mutations (addReaction/addStar/createIssue)	refused (no GH_TOKEN)	BLOCKED	✅

Overall: PASS

Part B refusals are gateway-enforced (write tools absent from MCP tool list, Error[-32602]). Parts D/E blocked by unauthenticated gh CLI.

References: §30961042703

🔒 mcpg read-only stress (docker-sbx runtime) by Read-Only Stress: docker-sbx runtime