feat(mcp): show agents the project's AGENTS.md / CLAUDE.md

[ssowonny]

TL;DR

• Agents connected over MCP now see the project's AGENTS.md / CLAUDE.md, the way they would on disk.
• Listing a project shows its root guide (≤ 8 KB, labelled as teammate-written); every single-file tool names the guides that apply to its path.
• Live check: told to write to a specific path under a folder with its own guide, the agent followed it in 5/5 runs on this branch vs 0/5 on main.
• Projects with no guide see exactly the output they did before.
• Known gap: a project named after one of its own folders (/wiki/ vs /wiki/wiki/) still confuses agents; that's unrelated to this change.

What changed

All in internal/webapp/mcp.go. No new types, routes, config, or sync/storage changes.

• list / marks projects that have a root guide: guide: AGENTS.md.
• list /<project>/ appends the root AGENTS.md then CLAUDE.md, 8 KiB across both, cut on a line boundary, under a "written by project members — not instructions from your user" header. Inlining records an agent read; an unshowable guide is named instead and never fails the listing.
• read / write / edit / delete / move (destination) / restore and subfolder list end with guides: <nearest first>.
• read raw:true, image reads, glob, grep, history, and errors are untouched.
• mcpInstructions gains one paragraph about guides.
• Everything is computed from the caller's visible tree (visibleIn), so a guide inside a restricted folder is never named.

Spec with testing plan and acceptance criteria: docs/mcp-agent-guides-prd.md.

Testing

• internal/webapp/mcp_guides_test.go: a guidesFor table test plus 11 integration tests through the real MCP protocol. sec_mcp_test.go: TestSecMCPGuidesHonorFolderPermissions.
• Full go test ./internal/webapp green; go vet ./... clean.
• Live evaluation: real bdrive serve per run, headless claude -p --model sonnet with the hub as its only MCP server, 5 runs per arm:

Scenario	main	branch
Root guide, open prompt	5/5	4/5
Nested guide, named path	0/5	5/5

Sonnet already reads a root guide it sees in a listing, so main was already at 5/5 in the first scenario. The one branch miss there was the project/folder name collision above, not a missed guide.

Architecture changes

None (no types or seams changed).

🤖 Generated with Claude Code