Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden, and it does disclose one important trait: the operation may be asynchronous, yielding a session handle to be waited on. It says nothing about side effects, permissions, cost, or whether repeated runs are safe (the idempotency_key hints at this, but the description never mentions it), so the burden is only partly met.

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?

Two short sentences, front-loaded with the purpose and return behavior before the parameter detail. No filler, every clause adds information.

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?

For a five-parameter tool with zero annotation coverage, the description leaves substantial gaps: budget parameters (max_steps, max_time_s), idempotency semantics, and side effects/cost are all unexplained. The output schema excuses it from describing return values, but not from the missing input semantics.

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 description coverage is 0% and the description only explains one of five parameters, `agent`, though it does so well (name from list_agents, name:N revision syntax). The required `task` and the optional max_steps, max_time_s, and idempotency_key are undocumented everywhere, leaving the agent to guess their meaning and units.

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 verb+resource ('Start an agent on a task') and immediately characterizes the outcome ('return the answer or a session handle to wait on'), which also separates it from the sibling wait_for_session. The revision syntax (name vs name:N) further pins down exactly what starting an agent means here.

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?

Tells the agent where the `agent` value comes from (list_agents) and that the default is the latest revision, which is real routing context. It stops short of explicit when-not-to-use guidance or naming wait_for_session / cancel_session as follow-up alternatives for the session-handle path.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.