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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the description's job is to add context. It does so by enumerating the full returned payload, which matters here because there is no output schema. It stops short of noting not-found/error behavior or whether the response is a superset of nullable fields.

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 compact clauses, front-loaded with the resource and scope, with the returned fields adding real information rather than filler. The raw endpoint path is slightly extraneous but costs almost nothing.

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 single-parameter read tool with full annotation coverage and complete schema documentation, this is close to sufficient: it tells the agent what it gets back despite the absence of an output schema. Minor gaps remain around error/not-found behavior and whether absent fields are null or omitted.

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?

There is a single parameter with 100% schema description coverage, including length bounds and a pointer to pobuca_list_contacts as the source of the id. The description adds no additional semantics beyond 'by id', which is the expected baseline when the schema already documents the parameter fully.

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 ('One contact by id') and enumerates exactly what comes back (phones, emails, addresses, organization, team, tags, custom fields), which separates it from the list tool. It never names a sibling tool, so the differentiation is inferred from scope 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?

Retrieving one record by id implies its own use case, and the schema note 'Contact id (from pobuca_list_contacts)' hints at the workflow. However, the description itself gives no explicit when-to-use guidance or alternatives (e.g., use pobuca_list_contacts to search, this tool when the id is already known).

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