MCP v2 tools and lifecycle

The endpoint is:

https://api.txcast.com/mcp/v2

Use a newly authorised OAuth access token or v2 manual key. Legacy /mcp credentials are revoked at cutover. OAuth discovery, PKCE, token rotation, and revocation remain transport concerns; workflow state never depends on one persistent MCP connection.

Tool discovery

tools/list is filtered by the scopes the credential can currently exercise. Every organisation-scoped input includes organisationId. Visibility means a tool is available somewhere, not that it is authorized for every organisation.

The v2 catalogue covers audit reads; controlled-account, address-book, and contract inspection and administration; workflow validation and linear version history; atomic run creation; effect inspection; and source refresh. It deliberately contains no human-response, wallet/Safe action, signature, signing, or broadcast tools.

Mutations

Mutating tools require caller provenance and a stable idempotency key for the exact semantic operation. Workflow and run mutations additionally require the latest CAS/version fields returned by a read.

Use one key for one exact operation. After a timeout, retry identical input with the same key. After a real version conflict, read current state and choose whether a new operation is still appropriate.

Confirmation boundary

MCP tool annotations are hints to the host, not authorization. Keep host confirmation enabled for registry changes, workflow create/save/restore/fork, run start/cancel, and refreshes. Server-side scope, account-grant, membership, ownership, CAS, and capability checks remain authoritative.

Wallet interactions and human.* effects must be completed by eligible people in txcast’s browser UI.

Reconnect

A reconnecting host can call tools/list, get_workflow, get_run, and list_run_effects to recover current state. Do not cache workflow, run, effect, or attempt versions across unrelated sessions.