acme_get_contact

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

readOnlyHint already establishes the safe-read profile, and the description adds the meaningful detail that the full record is returned ('every field'), hinting at a potentially large payload. It stops short of mentioning invalid-id error behavior, which the output schema does not necessarily cover.

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?

Two short sentences, zero padding, with the core action front-loaded and the disambiguation rule immediately after. Nothing could be removed without losing information.

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 one-parameter read tool with annotations, a 100%-covered schema, and an output schema handling return values, the description covers the only real decision an agent faces: id known vs. not known. Nothing essential to correct invocation is missing.

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?

With 100% schema coverage, the single contact_id parameter is already fully documented in the schema, including the 'c001' example format. The description's 'by its id' and 'from search results' restate rather than extend that, so baseline 3 applies.

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 ('Get every field of one contact by its id') and adds the scope 'every field', which tells the agent the result is a full record rather than a projection. The second sentence explicitly separates it from the sibling search tool by input type.

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 both the positive condition ('use this when you already have an id, for example from search results') and the exclusion with the named alternative ('If you only know a name or company, use search instead'). The agent needs no inference to pick between this and acme_search_contacts.

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