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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered elsewhere. The description adds only the slug-provenance relationship to list_companies, saying nothing about response shape, error behavior for unknown slugs, or localization effects beyond the schema's 'Language of the answer'.

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 tight sentence with the scope and the slug source front-loaded; no redundant restatement of the name or title and nothing to trim.

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?

For a simple two-parameter read tool with rich annotations, the definition covers what it does and where the identifier comes from. With no output schema, it could say slightly more about what 'read about' returns, but the gap is small for this complexity level.

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 both parameters are already documented, including the language enum with its default. The description's only added meaning is that the slug originates from list_companies, which is useful but marginal over the structured data.

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 ('Read about one company') with explicit singular scope, and distinguishes itself from the sibling list_companies by tying its input to that tool's output. An agent can tell immediately this is the detail-fetch counterpart to the list tool.

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?

The phrase 'by the slug list_companies returned' gives a clear usage path: call list_companies first, then fetch details here. It lacks explicit exclusions (e.g., when to use search_knowledge or get_article instead), which keeps it from a 5.

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