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

Annotations only say readOnlyHint=false and openWorldHint=true; they say nothing about cost. The description adds the crucial trait that this SPENDS the user's coins and that expected_total acts as a price-change guard, plus the transcribe surcharge. That is exactly the behavioral context annotations cannot carry.

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 sentences, zero padding, cost warning front-loaded ahead of the pricing procedure. Every clause carries operational information an agent needs before invoking.

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?

Covers prerequisites, cost, and where to read the result (poll get_breakdown), which partly compensates for the absent output schema. It stops short of covering repeat invocation, what 'finished' means operationally, or error modes beyond the price-change case.

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%, so baseline is 3, but the description goes further by explaining where expected_total comes from and what happens if it mismatches, and by tying breakdown_id to a 'finished'/'no AI read yet' state. It does not add anything for funding, purpose, prompt_lang or label_model beyond the schema.

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?

Specific verb+resource: 'Add the AI read of every shot to a finished free breakdown.' It also differentiates itself from siblings by naming estimate_breakdown, get_breakdown and list_breakdowns and describing the exact relation to each. An agent can place this tool precisely without opening another schema.

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?

Explicit workflow: price first with estimate_breakdown on the breakdown's source_url from get_breakdown or list_breakdowns, pass that total as expected_total, then poll get_breakdown. The failure mode ('if the price changed, nothing is spent') is stated outright, so the guard condition is unambiguous.

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