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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds value by explaining the response structure (`success`, `found`, `person`), the conditional availability of contact info, and the dual text/structured content views. It also notes the MCP Apps rendering behavior. This goes beyond annotations without contradicting them.

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?

The description is well-structured and front-loaded with the core purpose. It includes necessary details about output format and rendering without excessive verbosity. The sentences are purposeful, though the rendering note for MCP Apps could be considered slightly tangential; overall it earns a 4.

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?

Given the tool's simplicity (one parameter, read-only, output schema provided), the description is fairly complete. It explains what data is returned, when certain fields appear, and how results are presented. It does not mention error handling or edge cases, but those are minor for this type of retrieval tool. The output schema further fills any gaps, so a 4 is justified.

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 description coverage is 100% and the only parameter (`username`) already has a clear description with an example. The tool description reiterates the purpose but does not add new semantic details about the parameter itself. The baseline of 3 is appropriate because the schema carries the parameter documentation.

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 uses a specific verb ('Retrieve'), names the resource ('full public profile for a username'), and enumerates what the profile contains (skills, experiences, projects) plus conditional contact fields. This clearly distinguishes it from the sibling tools (search_people, match_people, create_profile_draft) which serve different purposes.

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 description implies usage by stating 'for a username' — the agent can infer this is the tool to use when a specific username is known. However, it does not explicitly state when to avoid this tool or name alternatives, such as 'use search_people when you need to discover profiles'. The guidance is implicit rather than explicit.

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