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

Beyond the readOnly/idempotent annotations, it discloses that no generation is run, what the response contains (diagnosis, credited fixes, revised prompt), and the escalation ordering (same-model fixes, then mode change, then model switch with consistency cost stated). That escalation policy is behavior an agent cannot infer from any structured field.

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?

Front-loaded with the alias and one-line purpose, then the input expectations and the return/escalation contract. It is a long single paragraph, but nearly every clause carries non-redundant information; the only mild waste is minor repetition between "Fix a generated shot" and the alias sentence.

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?

There is no output schema, so the description must describe the return, and it does precisely: diagnosis, specific prompt changes with attribution, revised prompt, and a ranked escalation ladder. Inputs, behavior, and outputs are all covered for a 7-parameter tool.

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 the baseline is 3, but the description earns more by explaining the intended content of `issue` (plain-word symptoms like "feet sliding", "face drifted") and grouping which fields belong together (`prompt`/`model`/`mode`/symptom plus optional frame notes). It adds meaning rather than restating types.

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 ("Fix a generated shot that came out wrong") and, critically, declares itself an alias of refine_shot, which disambiguates it from the sibling of the same function. An agent knows exactly what it does and how it relates to refine_shot without opening either 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?

Gives clear context (a shot already came out wrong) and tells the agent what to supply: the prompt, model, mode, and the issue in plain words, plus optional frame notes. It never states when NOT to use it versus best_prompt/plan_shots, but the alias declaration does most of the routing work.

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