Look up a public Threads profile

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

Goes far beyond the annotations (readOnlyHint, openWorldHint, destructiveHint) by disclosing critical behaviors: handle matching is EXACT so display names fail, the resolution of bare/'@'/link formats, and a crucial error-handling note (if nothing comes back, do not assume absence – read the note for approval state). It also reiterates read-only and zero cost, consistent with annotations, and clarifies it's not a scraper.

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 long but densely packed with actionable information. It front-loads the core purpose, then moves through usage context, input format caveats, error handling, and prerequisites. Every sentence contributes value, though some phrasing could be tightened (e.g., the dual mention of 'competitor research'). Overall it is structured well and not bloated.

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 tool with a single parameter and no output schema, this description is exceptionally complete: it specifies the accepted input formats, the data returned, the prerequisite connection, the cost, the error-prone scenario and how to interpret the note, and the relationship to a sibling tool. An agent can confidently invoke this tool correctly with no missing guidance.

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?

The schema already fully describes the username parameter with examples, but the description adds meaningful semantics: it explicitly states that display names will NOT resolve due to exact matching, and reinforces the accepted formats. This goes beyond a simple restatement of the schema, giving the agent the resolution rules needed to avoid a failed call.

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 ('Read') and resource ('public Threads account'), and enumerates the exact data fields returned (name, bio, avatar, verified badge, follower count, lifetime likes/quotes/reposts/views). It also distinguishes itself from the sibling list_threads_profile_posts by naming it explicitly as the companion for reading posts, making the tool's purpose 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?

Provides clear context: competitor and creator research on Meta's own data, and directs the agent to follow with list_threads_profile_posts to draft a brand's answer. It also states prerequisites ('Needs Threads connected') and cost implications ('0 credits'). However, it does not explicitly mention when not to use this tool, or name direct alternatives for profile-related queries, so it stops short of full exclusion guidance.

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