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

Annotations cover the safety profile (not read-only, not destructive, not idempotent by default), and the description adds material context beyond them: the task is asynchronous, requires authentication, and may consume paid model capacity. That cost/auth disclosure is genuinely useful. It stops short of describing failure modes or quota behavior.

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?

Three short sentences, each earning its place: what it does, the cost implication, and the follow-up sequence. Front-loaded with the core action and zero filler.

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?

With no output schema, the description usefully directs the agent to the status and result tools, and flags the paid-capacity risk. Nothing essential is missing for correct invocation, though run lifecycle states or auth prerequisites are left implicit.

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 100%, with all three parameters documented in the schema itself, including the idempotency_key retry semantics. The description adds no per-parameter meaning beyond that, so the baseline of 3 applies.

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 and resource: "Queues an authenticated asynchronous task." Combined with the title ('Create a Fable 5.1 run') an agent can identify it as the run-creation entry point. It doesn't sharply differentiate from siblings beyond naming the follow-up tools, and 'task' remains somewhat abstract.

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?

Gives an explicit post-invocation workflow: poll with agentfarm_get_run_status, then read agentfarm_get_run_result. It does not state when NOT to use it or how it relates to agentfarm_cancel_run, but the sequencing guidance is clear and actionable.

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