Look up a public profile

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

Beyond the readOnly/idempotent annotations, the description discloses a rate limit, a minimum-follower filter, and an expanded-access requirement for non-Meta accounts. It does not describe error behavior for missing or non-public profiles, but the annotations and constraints cover the main safety-relevant behavior.

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?

Three sentences, each contributing a distinct piece of information: what the tool returns, the public/minimum-follower constraint, and the access/rate limitations. No filler or redundancy.

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 explicitly lists the return fields (follower count and seven-day totals for views, likes, quotes, reposts) and covers limiting conditions. For a simple single-parameter-required lookup, nothing needed to invoke it correctly 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?

Schema description coverage is 100%, so the parameters are already fully documented in the input schema. The description only restates the 'by username' lookup theme and adds no new semantics for the account or username parameters.

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 combined title and description make clear this tool looks up a single public Threads profile by username and returns follower count plus seven-day engagement totals. It is differentiated from read siblings by focusing on a profile resource rather than posts or insights, though it does not explicitly name an alternative.

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 gives clear context for when to use the tool: to fetch a public profile by username with follower and engagement metrics. It also states important access constraints (100+ followers, 1,000-lookup cap, expanded-access limitation), but it does not explicitly say when to prefer a sibling tool instead.

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