[samuv]

Tracking: #1851

Stage

Plan / Interface (draft) for a Bounded, Split Studio change. This PR targets main and contains only the acceptance plan and its index entry. It starts from the merged chat contract associated with #1847. The decision record is None: ADR 0351 already sets the one-origin browser/BFF boundary and published-SDK rule.

The plan stays draft until #1850's final shared-panel interface is merged and reconciled, and a published SDK contains the separate tool-list prerequisite. Human review and merge of this Plan / Interface PR establish the implementation baseline; no implementation is included here.

Contract and behavior

• Add one connection-scoped, read-only GET /api/v1/mcp/inventory BFF projection through the published SDK. The source Zod schema, OpenAPI document, and generated browser client define servers, catalog-admitted tools, prompts, resources, and source revision/stale/reconciling status. The BFF calls only list operations; it never expands prompts, reads resource content, or executes tools.
• Keep the route behind Studio's existing session gate and per-request SDK credential context. Capability and online-state gates run before inventory reads. Fixed problem responses distinguish invalid request, expired session, disconnected runtime, unsupported MCP, and projection failure. A path-specific no-store middleware covers early 401/503 responses too. Transport URLs, structured credentials, diagnostics, tool schemas, prompt messages, and resource bodies stay out of the projection.
• Omit resources with malformed URIs, userinfo, query or fragment components, or a data: URI. Eligible resource identities remain exact. Fail projection on duplicate model-facing tool names, and require the separate tool-list release to expose only catalog-admitted tools so a shadowed name cannot produce a misleading insertion.
• Show a searchable server-first inventory in Studio chat: minimap, side panels, and session inspection #1850's shared panel on signed-in draft, editable chat, and inspect-only views. Server rows browse. Leaf rows insert only where a composer is editable; inspect-only views browse without insertion. Loading, empty, error with Retry, disconnected, unsupported, and online stale/reconciling states have distinct behavior.
• Add an Insert from MCP menu only to editable composers. Choosing a tool, prompt, or resource inserts an exact, type-labelled plain-text reference at the saved caret or selection through the existing draft model. It does not send a prompt or call a tool. The plan covers keyboard, IME, touch, Escape, focus, session switching, and desktop/mobile layout.

Sequencing and in-flight work

• docs(plan): define Studio minimap, side panels, and session inspection #1939 is the open Studio chat: minimap, side panels, and session inspection #1850 Plan / Interface PR; feat(studio): add session inspection panels and minimap #1942 is its stacked implementation PR. Their shared frame and mobile sheet are provisional. feat(studio): complete chat approvals, plan review, and Escape flow #1975 is also open and owns remaining chat approvals and Escape behavior. Reconcile their final merged props, focus return, and Escape priority before marking this plan proposed.
• Studio pins npm SDK 0.3.0. Published 0.4.0 adds source revision/stale/reconciling fields, but neither published version has client.mcp.listTools. The daemon RPC and SDK method need a separate release first. Open dependency update chore(deps): update dependency @stacklok-oss/mecatl-sdk to ^0.4.0 - autoclosed #1965 to 0.4.0 alone does not unblock Studio chat: browse MCP inventory and insert into a draft #1851.
• Recommendation: review this independent contract now, then wait for the shared panel, Escape work, and published tool-list SDK before Studio chat: browse MCP inventory and insert into a draft #1851 implementation. No open PR currently supplies that tool-list prerequisite.

Review and verification

• The acceptance-plan checker passed: all 12 ACs have verification lines and all seven interface categories are populated. Its named-Go-test warning is advisory for this TypeScript-focused plan.
• The acceptance-plan regression fixture suite passed.
• CGO_ENABLED=0 task docs passed, including generated-reference checks and strict links: 590 documents and 5,761 references, with no broken links, anchors, or orphans. Plain task docs hit this host's macOS CGO linker; the successful run used CGO disabled. git diff --check passed.
• One devil's-advocate pass and one security spot-check were folded into the error mapping, mobile-sheet expectation, tool collision rule, resource-URI policy, and early no-store coverage. Runtime and UI acceptance proofs are specified for the later implementation PR.

Implementation and merge remain separate human-reviewed steps.