Establish a durable subscription cursor for a thread so agents can resume message tracking and maintain coordination across sessions.
Create a durable per-thread subscription cursor.
| Name | Required | Description | Default |
|---|---|---|---|
| thread_id | Yes | ||
| binding_token | No | Opaque token returned by this agent's join_session or plan_session. Required for reliable identity when logical agents share an MCP connection. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses that the operation creates a durable, thread-scoped cursor, which is meaningful side-effect information. However, with no annotations, it does not explain idempotency, whether an existing subscription is replaced, or what happens after creation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single concise sentence with no filler; the core action and scope are front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Adequate for a simple creation operation, but without annotations or an output schema it leaves the return value, follow-up usage, and lifecycle behavior to inference.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 50%. The 'per-thread' wording clarifies the thread_id parameter, but the description adds little about the binding_token or its role beyond the schema description.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific action ('Create') and a clear resource ('durable per-thread subscription cursor'). It distinguishes itself from siblings like poll_thread and ack_thread by identifying that it creates rather than consumes a subscription, though it relies somewhat on the tool name.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance on when to call this tool, what preconditions exist, or how it relates to siblings such as poll_thread, ack_thread, or close_thread. The binding_token schema note adds context, but the description itself does not state usage conditions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.