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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description goes beyond them by disclosing what comes back — a per-fact source URL, as-of date and Reported/Tested label — which tells the agent the response carries provenance and trust metadata.

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?

A single sentence with no filler; the identification mode (slug or exact name) comes first and the return-shape detail follows, so it is well front-loaded.

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 rightly spends its words on the returned fields, and one-parameter input is fully covered by the schema. Minor gaps remain: nothing about behavior when the slug is unknown or whether name matching is case-sensitive.

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 coverage is 100%, so the schema already defines the single slug parameter. The description adds value by giving a concrete example value ('gemini-4-argon') and clarifying that either a slug or an exact name is accepted, which helps an agent construct a valid value.

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?

The description states a specific verb ('Get') and resource ('one model') and makes the singular, identifier-based lookup explicit, which separates it in spirit from sibling list tools. It stops short of naming those siblings, so differentiation is inferable rather than stated.

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?

Usage is only implied: 'Get one model by slug' suggests looking up a specific known model rather than browsing or comparing. There is no explicit when-to-use vs latest_models/compare_tools guidance and no exclusion conditions.

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