feat(cursor): refresh plugin contract coverage against the 2026-09-02 public docs (#189)

Validate and project Cursor subagentStart/subagentStop through their documented
subagent_* envelopes and output channels (permission deny + user_message;
followup_message) in event routes, config-hook wrappers, playground codecs, and
lifecycle starters. Add the cursor.* config extension for schema-admitted
manifest metadata (author, homepage, repository, license, keywords, publisher,
category, tags, minClientVersions) with cursor.manifest.* diagnostics. Pin the
complete 21-event Cursor hook inventory with cloud availability, hook options,
plugin formats, discovery, variables, marketplace limits, distribution and
local-install surfaces, canvases, and the G5-gated agents component as dated
capability rows mirrored through the unified bundle. Cursor adapterRevision
1.9.0, plugin 1.22.0.

Author: ScriptedAlchemy

.changeset/cursor-contract-refresh.md

@@ -0,0 +1,19 @@
+---
+"agent-bundle": minor
+---
+
+Refresh the Cursor plugin contract against the public docs retrieved 2026-09-02
+(#189). Cursor `subagentStart`/`subagentStop` now validate their documented
+`subagent_*` envelopes and project through their real output channels
+(`permission: "deny"` + `user_message`; `followup_message`), with wrapper,
+playground, and lifecycle-replay fixtures. A new `cursor.*` config extension
+emits schema-admitted manifest metadata (`author`, `homepage`, `repository`,
+`license`, `keywords`, `publisher`, `category`, `tags`, `minClientVersions`)
+into `.cursor-plugin/plugin.json` with `cursor.manifest.*` diagnostics. The
+Cursor capability table records every documented hook event (21) with cloud
+availability, hook options (`failClosed`, `loop_limit`, prompt hooks), plugin
+formats, component discovery, variables, marketplace manifest limits, team
+distribution and local-install surfaces, canvases, and the G5-gated agents
+component as dated `supported`/`unavailable` rows; the unified bundle mirrors
+each row and now intersects Cursor manifest metadata for real. Cursor
+`adapterRevision` 1.8.0 → 1.9.0, unified plugin 1.22.0 → 1.23.0.

README.md

@@ -55,6 +55,8 @@ Claude Code language servers are declared under `claude.lspServers`; the `claude
 
 Claude Code plugin defaults are declared under `claude.settings` and emitted as plugin-root `settings.json`, which Claude Code applies when the plugin is enabled. The pinned contract supports only `agent` and `subagentStatusLine`; Agent Bundle rejects any other key rather than shipping a default Claude Code would silently ignore, and it expands no path tokens here because `settings.json` is absent from the host's placeholder-substitution table. Because the plugin `agents/` component is still deferred, declaring `agent` also raises a warning: the referenced agent has to reach the plugin root some other way, such as a prebuilt payload.
 
+Cursor Plugin manifest metadata is declared under `cursor.*` and emitted verbatim into `.cursor-plugin/plugin.json` by the `cursor` target and the Cursor half of `plugin`: `author` (`name`, optional `email`), `homepage`, `repository`, `license`, `keywords`, plus the schema-admitted `publisher`, `category`, `tags`, and `minClientVersions` (for example `{ cursor: '3.13.0' }`). Every field is validated against the pinned `cursor/plugins` manifest schema before emission — `author.url`, non-HTTP URLs, empty strings, and loose semver are rejected with `cursor.manifest.*` errors, and an invalid block emits no partial metadata. The Cursor artifact never mixes Agent Plugin (`plugin.json`, `${PLUGIN_ROOT}`) paths or tokens into the Cursor Plugin format; the portable target owns that format. The full documented-surface contract matrix (every Cursor hook event, cloud availability, hook options, marketplace and team-distribution surfaces, canvases, agents) lives as dated `supported` / `unavailable` rows in `packages/agent-bundle/src/adapters/capabilities/cursor-2026-08-28.json`.
+
 The same config also owns the npm package build — no second bundler config, bin shims, or hand-rolled stdio lifecycles. `bin` and `lib` entries (or the conventions `src/cli.ts`, `src/index.ts`, and `src/mcp/<server-id>.ts`) emit executable `dist/bin/<name>.js` bundles and a library output alongside the host artifacts; an MCP entry that default-exports a server factory runs under a framework-owned stdio lifecycle; `tools.rsbuild` / `tools.rspack` is the one bundler escape hatch. [Entry conventions](docs/entry-conventions.md) is the full contract, and [Framework mode](docs/framework-mode.md) is the whole authoring model on one screen: structure in config and conventions (`src/skills/<name>/SKILL.md` ships with no declaration at all), JSX only where something is rendered.
 
 ## Commands

docs/canvases/agent-bundle-walkthrough.canvas.tsx

@@ -742,8 +742,8 @@ else try { output = await requestEventRuntime({ ... }); }
             [<Text as="span" style={{ fontFamily: MONO }} size="small">tool/before</Text>, "PreToolUse", "PreToolUse", "preToolUse", "—"],
             [<Text as="span" style={{ fontFamily: MONO }} size="small">tool/after</Text>, "PostToolUse", "PostToolUse", "postToolUse", "—"],
             [<Text as="span" style={{ fontFamily: MONO }} size="small">stop</Text>, "Stop", "Stop", "stop", "—"],
-            [<Text as="span" style={{ fontFamily: MONO }} size="small">agent/start</Text>, "SubagentStart", "SubagentStart (adds turn_id, model, permission_mode)", "subagentStart", "—"],
-            [<Text as="span" style={{ fontFamily: MONO }} size="small">agent/stop</Text>, "SubagentStop", "SubagentStop", "subagentStop", "—"],
+            [<Text as="span" style={{ fontFamily: MONO }} size="small">agent/start</Text>, "SubagentStart", "SubagentStart (adds turn_id, model, permission_mode)", "subagentStart (subagent_id/subagent_type envelope; permission deny)", "—"],
+            [<Text as="span" style={{ fontFamily: MONO }} size="small">agent/stop</Text>, "SubagentStop", "SubagentStop", "subagentStop (status/loop_count envelope; followup_message)", "—"],
             [<Text as="span" style={{ fontFamily: MONO }} size="small">workspace/open</Text>, "unavailable: no such event", "unavailable: no such event", "workspaceOpen (observe-only; optional pluginPaths return not modeled)", "unavailable: spec defines no hooks"],
           ]}
         />
@@ -758,8 +758,8 @@ else try { output = await requestEventRuntime({ ... }); }
                 ["tool/before", "yes, reason required", "yes (when not denying)", "Claude + Codex; dropped on Cursor"],
                 ["tool/after", "—", "—", "all hosts"],
                 ["stop", "yes — keeps the agent working (Cursor: followup_message)", "—", "—"],
-                ["agent/start", "no host can block subagent creation", "—", "all hosts"],
-                ["agent/stop", "Claude + Codex (keeps subagent running); Cursor cannot", "—", "Claude + Cursor; Codex schema rejects it"],
+                ["agent/start", "Cursor only (permission: deny + user_message); Claude + Codex cannot", "—", "Claude + Codex; Cursor documents no channel"],
+                ["agent/stop", "Claude + Codex (decision: block keeps subagent running); Cursor (followup_message auto-continue)", "—", "Claude only; Codex schema and Cursor docs reject it"],
                 ["workspace/open", "—", "—", "no channel — observation only (Cursor)"],
               ]}
             />

examples/rsc-agent-runtime/README.md

@@ -246,8 +246,8 @@ Host/Origin allowlists mitigate DNS rebinding and cross-origin requests, but the
 | `task/create` | Unavailable | `TaskCreated` (deny) | Unavailable |
 | `task/complete` | Unavailable | `TaskCompleted` (observe-only; blocking is exit-code-only) | Unavailable |
 | `agent/idle` | Unavailable | `TeammateIdle` (deny via continue:false) | Unavailable |
-| `agent/start` | `subagentStart` | `SubagentStart` | `SubagentStart` |
-| `agent/stop` | `subagentStop` | `SubagentStop` | `SubagentStop` |
+| `agent/start` | `subagentStart` (deny via `permission: "deny"`; no context channel) | `SubagentStart` (context) | `SubagentStart` (context) |
+| `agent/stop` | `subagentStop` (deny via `followup_message`; no context channel) | `SubagentStop` (deny + context) | `SubagentStop` (deny) |
 | `workspace/open` | Supported (observe-only; native `pluginPaths` return not modeled) | Unavailable | Unavailable |
 
 Cursor's native `workspaceOpen` is sessionless and its optional `pluginPaths`
@@ -260,7 +260,15 @@ block subagent creation. Their `agent/stop` routes can continue the subagent
 with the native `decision: "block"` plus `reason` contract. Codex
 `SubagentStop` exit-0 output is always JSON; its generated 0.147.0 output
 schema has no `additionalContext` field, so the route projection rejects that
-unsupported effect rather than silently fabricating one.
+unsupported effect rather than silently fabricating one. Cursor inverts the
+pair: its `subagentStart` envelope (`subagent_id`, `subagent_type`, `task`,
+`parent_conversation_id`, `tool_call_id`, `subagent_model`,
+`is_parallel_worker`) accepts `permission: "deny"` plus `user_message`, and its
+`subagentStop` envelope (`status`, `loop_count`, `summary`, `modified_files`,
+`agent_transcript_path`) accepts only `followup_message`, which Cursor consumes
+when `status` is `completed` and caps with `loop_limit` (default 5). Neither
+Cursor event documents an additional-context channel, so `Agent.Context` fails
+closed on Cursor for both.
 `session/end` and `prompt/submit` are event-route-only families and do not add
 `config.hooks.sessionEnd` or `config.hooks.promptSubmit` handler keys.
 `session/end` rejects every result effect because each native event is

packages/agent-bundle/README.md

@@ -574,7 +574,7 @@ observed host version (`observedVersion`) and target, while adapters carry a mon
 `adapterRevision`. Git already versions repository-owned content; hashing it again inside the
 repository is self-referential and causes churn on every table edit.
 
-`AgentBundleConfig` merges bundled portable, Codex, and Claude declarations
+`AgentBundleConfig` merges bundled portable, Codex, Claude, and Cursor declarations
 through `AgentBundleConfigExtensions`. `TargetRegistry` owns the unique
 extension descriptor and adapter for each target. Ordinary projects need no
 extension key; extension values are strict finite JSON and host-specific values