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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond them: it states the call is free, requires no API key, and that failures return an error naming the id rather than silently failing. It stops short of describing response shape or rate limits, so 4 rather than 5.

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?

Four short sentences, front-loaded with what is returned and then why/when to use it. Every sentence carries distinct information (content, routing, cost/auth, error behaviour) with no redundancy.

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 must say what comes back, and it does ('the raw model object, or an error naming the id'). Combined with the auth/cost note and the sibling routing, an agent has everything needed to invoke it correctly.

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% and there is a single required parameter, so the schema already documents that 'model' is the id from synap_list_models. The description adds no syntax, casing, or format detail beyond what the schema states, making this the baseline 3.

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 precise verb and resource ('Return the complete catalogue record for one Synap model') and enumerates the exact fields covered (pricing, limits, parameters, quantisation, retention, readiness). It also explicitly positions itself against the sibling synap_list_models, so an agent can distinguish it 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 an explicit trigger ('Use this after synap_list_models when you need details the summary leaves out') and names the alternative tool plus the condition that selects it. No inference is required to choose between the two.

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