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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered structurally. The description adds the endpoint and list scoping, but its claim of 'all fields' is misleading given the optional fields filter in the schema, and there is no note on error behavior for unknown ids.

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, front-loaded sentences with no filler. The trailing endpoint restates schema structure somewhat redundantly, but it costs little.

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?

This is a simple read tool with annotations and a small schema, so the burden is low. With no output schema, though, the description carries the return-value explanation and does so inaccurately ('all fields' when filtering is possible), leaving a real gap for an agent shaping the response.

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 coverage is only 33% — list_id and contact_id are typed but undocumented there, so the description does add value by mapping them to the path template. However, 'with all fields' conflicts with the documented fields parameter, and no format or id-source detail is given.

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 within a list') plus the underlying endpoint, which makes the single-vs-many distinction against vision6_list_contacts inferable. It stops short of naming that sibling explicitly, so the differentiation is implicit 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?

There is no explicit when-to-use/when-not-to-use guidance and no mention of where list_id and contact_id come from (e.g. vision6_list_contacts). The usage is strongly implied by 'by id within a list', but the agent must infer the lookup workflow.

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