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

Annotations already declare readOnlyHint=true, so the description's bar is lower. It adds context that the profile is 'public' and that contact details are intentionally excluded (live on linked page). This gives the agent useful behavioral expectations beyond the annotation without contradiction.

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 sentences, front-loaded with main purpose, then a list of profile contents, and a note about contact details. Every word earns its place with zero fluff. Excellent structure for quick scanning.

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 tool with an output schema, the description is complete: it lists the main data fields, indicates the source of the username, and states what is NOT included (contact details). The output schema covers return values, so no further explanation is needed. Fully adequate for tool selection and invocation.

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 100% with 'username' described as 'Expert username from search_experts'. The description repeats this in prose ('by username (as returned by search_experts)') but adds no new semantic detail. Baseline of 3 is appropriate since the schema carries the parameter meaning.

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?

Description clearly states 'Full public profile for one therapist/expert by username' with specific verb 'Get' (from title) and resource. It distinguishes from siblings like search_experts (which returns lists) and get_facility (facilities). Mentions specific fields included (credentials, license type, etc.), so purpose is unambiguous.

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?

Explicitly says username is 'as returned by search_experts', establishing a prerequisite and workflow. It also notes 'Contact details live on the linked profile page', telling the agent when NOT to use this tool (if contact details are needed). This is clear when-to-use vs alternative guidance.

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