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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the base safety profile is covered. The description adds valuable behavior beyond annotations: it requires an API key, takes no parameters, only ever describes the caller, and errors on missing/invalid keys, framing the tool as a quick authentication test.

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 sentences, front-loaded with the core purpose and return payload, then usage context, then constraints and error behavior. No filler or redundant restatement of the tool name; every sentence adds operational value.

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 parameterless read-only tool with rich annotations and no output schema, the description is complete: it lists return fields, specifies authentication requirements, states invocation constraints (caller only), and explains error semantics. Nothing important 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 are zero parameters and schema coverage is effectively 100%, so the schema carries no burden. The description reinforces this by explicitly saying 'takes no parameters' and explaining the error behavior when a key is missing, which is sufficient for a parameterless tool.

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 opens with a specific verb ('Fetch') and a precise resource ('authenticated account's own creator profile'), then enumerates the exact fields returned (id, username, display name, bio, public profile URL, stripe_connected). It also explicitly distinguishes itself from any hypothetical other-profile lookup, which fully separates it from sibling tools.

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?

Gives three concrete use cases: confirming which account a key belongs to, retrieving your own profile id for UUID-accepting tools, and checking stripe_connected before discussing paid posts. It also states a clear exclusion ('there is no tool here for looking up someone else's profile'), preventing the agent from selecting it for the wrong task.

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