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. The description adds real value by scoping the return ('latest 10 conversations'), which tells the agent results are bounded and partial. It says nothing about permission requirements or error behavior for an invalid id.

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 dense sentence with the payload contents front-loaded after the verb+resource, plus a short trailing note on the underlying GraphQL query. Every clause carries information; the GraphQL reference is minor but harmless.

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 must describe the return value, and it does so concretely: profile fields, tags, contributions, and the latest 10 conversation ids. Combined with annotations covering the safety profile, an agent has enough to call this correctly; only cross-tool selection guidance 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?

There is one parameter at 100% schema description coverage, so the schema already documents contact_id fully. The description restates the by-id access pattern but adds no format, source, or constraints beyond the schema — baseline 3 for high coverage.

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 the returned payload (profile fields, tags, contributions, latest 10 conversations), which makes it distinguishable from list_contacts and find_contact by shape. It stops short of naming those siblings explicitly.

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 by-id framing implies this is the follow-up to a search/list result rather than the discovery tool, and it helpfully routes the agent to superphone_get_conversation for the embedded ids. However, it never states when to prefer find_contact or list_contacts, so the alternative-selection logic is left to inference.

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