MCP `explore` gains a `tree` view: an app's fork chain in the page's own words, no new tool #11405

MCP explore now takes { kind: "tree", app: "owner/name" } and returns that app's fork chain as plain rows. There is no new tool. One part of the spec is not met: "last taken" is not a real take time, because the forge doesn't record one. It is the time the fork's default branch last moved, which the forks page labels "pushed".

The new tests, mcp-size, mcp-table and the other tests scripts/fast.ts picked all pass, and tsc and the gate are clean. I did not run bun scripts/design-lint.ts, since nothing under src/web changed. The forks page and the answer share the "follows" and "standing" wording but not the "pushed" time, which the page prints as a relative time and the answer as an ISO timestamp.

What it returns. The answer is { app, upstream, forks, truncated }. Each row is { repo, follows, standing, updatedAt }.

• upstream is the chain above the app, nearest first, ending at the highest ancestor the caller can read.
• forks are the app's direct forks, at most 60. truncated is true when more exist.
• follows uses the Following card's wording ("Follows x automatically", "Proposes updates from x", "Does not follow x"). The top of a chain says "This repository follows nothing."
• standing uses the forks page's drift wording ("2 ahead · 0 behind", or "standing unknown").
• updatedAt is the fork's last-moved time described above.

Privacy. A fork the caller can't read is not a row. An app the caller can't read, or one that doesn't exist, answers not_found.

Where it lives.

• The reader is src/actions/fork_tree_rows.ts.
• The tool change is in src/http/mcp/tools/explore.ts.
• docs/MCP.md names the view, and I regenerated its tool table with scripts/mcp-table.ts.
• test/mcp-tree.test.ts covers the chain, the wording, a private fork hidden from a stranger, and an unreadable app. Its parity check fetches /alice/lib-mid/forks and confirms the page carries the same "follows" and "standing" text.

Size. The description change stays inside the existing ceilings; I raised none. Most of the new text is in the tool's doc line, which clients never receive.

Left alone. The existing fork_tree and forks tools, which answer in other shapes (whole tree, and drift pages), are unchanged.

Try it. Call explore with { "kind": "tree", "app": "alice/lib-mid" } and compare the rows with /alice/lib-mid/forks.

Closes #11377

MCP explore now takes { kind: "tree", app: "owner/name" } and returns that app's fork chain as plain rows. There is no new tool. One part of the spec is not met: "last taken" is not a real take time, because the forge doesn't record one. It is the time the fork's default branch last moved, which the forks page labels "pushed".

The new tests, mcp-size, mcp-table and the other tests scripts/fast.ts picked all pass, and tsc and the gate are clean. I did not run bun scripts/design-lint.ts, since nothing under src/web changed. The forks page and the answer share the "follows" and "standing" wording but not the "pushed" time, which the page prints as a relative time and the answer as an ISO timestamp.

What it returns. The answer is { app, upstream, forks, truncated }. Each row is { repo, follows, standing, updatedAt }.

• upstream is the chain above the app, nearest first, ending at the highest ancestor the caller can read.
• forks are the app's direct forks, at most 60. truncated is true when more exist.
• follows uses the Following card's wording ("Follows x automatically", "Proposes updates from x", "Does not follow x"). The top of a chain says "This repository follows nothing."
• standing uses the forks page's drift wording ("2 ahead · 0 behind", or "standing unknown").
• updatedAt is the fork's last-moved time described above.

Privacy. A fork the caller can't read is not a row. An app the caller can't read, or one that doesn't exist, answers not_found.

Where it lives.

• The reader is src/actions/fork_tree_rows.ts.
• The tool change is in src/http/mcp/tools/explore.ts.
• docs/MCP.md names the view, and I regenerated its tool table with scripts/mcp-table.ts.
• test/mcp-tree.test.ts covers the chain, the wording, a private fork hidden from a stranger, and an unreadable app. Its parity check fetches /alice/lib-mid/forks and confirms the page carries the same "follows" and "standing" text.

Size. The description change stays inside the existing ceilings; I raised none. Most of the new text is in the tool's doc line, which clients never receive.

Left alone. The existing fork_tree and forks tools, which answer in other shapes (whole tree, and drift pages), are unchanged.

Try it. Call explore with { "kind": "tree", "app": "alice/lib-mid" } and compare the rows with /alice/lib-mid/forks.