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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered by structured data rather than the prose. The description adds the concrete endpoint (GET /v2/user/contact-details) and an injection warning about untrusted content, which is genuine extra guidance — though the warning mentions 'message text', which this tool does not appear to return, so it is slightly off-target.

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 fragments, front-loaded with what is read, followed by the endpoint and the safety note. Nothing redundant and nothing buried.

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 zero-parameter read with full annotation coverage and no output schema, the description says enough to call it correctly. Returned fields are only sketched ('ID and contact profile'), which is acceptable given the tool's simplicity but leaves the response shape slightly unspecified.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter semantics burden to carry. The description correctly implies a no-argument call scoped to the authenticated account.

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 names a specific verb and resource ('Read this authenticated account's ID and contact profile') and qualifies it with 'this authenticated account's', which separates it from the sibling smsglobal_get_contact that fetches an arbitrary contact. It is clear without opening a schema, though it never explicitly names the sibling it differs from.

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: the phrase 'this authenticated account's' suggests it is the tool for the caller's own profile, and 'Read-only' signals a safe fetch. There is no explicit statement of when to prefer it over smsglobal_get_contact, nor any prerequisite or exclusion.

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