edit-cad-in-partmode

name	edit-cad-in-partmode
category	code
description	Inspect, preview, commit, and verify an exact CAD change through PartMode's hosted MCP server. Use when someone asks an agent to create or modify a PartMode part, sketch, feature, assembly, drawing, or other schema-supported CAD document.

edit-cad-in-partmode

Make one bounded CAD change through PartMode while preserving revision history and exact runtime evidence. Read https://partmode.com/help#mcp-reference before the first edit and follow live tools/list and cad_capabilities schemas.

Required connection

This skill is operating guidance, not a PartMode login or tool connection. Before an agent continues, confirm that it can list PartMode MCP resources and tools. If it cannot, stop and use $connect-partmode-to-an-agent: create or sign in to an account at https://partmode.com/account with an account name and passphrase, create the least-powerful suitable agent key, store the one-time secret as PARTMODE_AGENT_KEY, and configure Codex with:

codex mcp add partmode --url https://partmode.com/mcp --bearer-token-env-var PARTMODE_AGENT_KEY

Restart the agent after adding the server. A browser-local project also requires a signed-in PartMode tab and visible approval; server-headless work requires an edit key created with the explicit headless grant. Never simulate CAD work from these instructions or claim completion without exact settled evidence returned by the connected PartMode tools.

Boundaries

• Work only in the project and session the person selected. Use visible browser approval unless they explicitly created a key with headless server access.
• Never invent an operation name, input field, entity identifier, or capability. A schema declaration or old example is not authority for the live release.
• Preview every mutation. Do not treat preview as commit, and do not retry an ambiguous mutation until the current document revision has been inspected.
• Treat screenshots, DOM rows, mesh counts, and success messages as presentation evidence, not proof that exact CAD completed.

Procedure

1. Write the requested change and its acceptance checks in concrete CAD terms: target project, entities, dimensions, units, intended topology or assembly relationship, artifact need, and what must remain unchanged. Record a revision-bound invariant and entity manifest for unrelated geometry.
2. Open one bounded browser-approved or headless session. Call cad_capabilities and confirm the required operation kinds and permissions are available within the remaining commit budget.
3. Inspect the current document with cad_inspect or cad_query. Capture the revision and exact identifiers returned by PartMode instead of guessing from labels or screen position.
4. Construct only operations advertised by the live capability manifest. Keep the transaction limited to the requested change and preserve unrelated document state.
5. Call cad_preview. Read validation diagnostics and exact preview evidence. If the preview changes more than requested or leaves a requirement unresolved, revise the transaction rather than committing it. Treat a preview as accepted only through the person's explicit approval or deterministic checks they agreed to before preview.
6. Commit only the accepted preview identity against its matching revision. If the revision is stale, inspect again. Halt for the person when a concurrent change overlaps a target or changes the acceptance criteria; otherwise preserve it, refresh the invariant manifest at the new source revision, and create a new preview from that revision.
7. Inspect the settled document after commit. Verify the new revision and the exact evidence relevant to the task: B-rep, persistent topology, dimensions, mass properties, mate state, drawing evidence, or document hash.
8. On an ambiguous transport failure, inspect revision and document state before retrying. On an expired session, open a new bounded session and rediscover capabilities. Use a visible Studio when a tool reports VISIBLE_STUDIO_REQUIRED.
9. Disconnect the session. Report the revision transition, exact checks, any limitation, and whether an artifact was separately exported.

Done

• The committed transaction matches an accepted preview and one known source revision
• The settled document has a verified new revision with exact runtime evidence
• The revision-bound invariant manifest proves unrelated state remained unchanged
• No ambiguous request was blindly retried and no unsupported operation was invented
• The session is disconnected and the result report names any remaining limitation