Verify the token and show the profile

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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds value by revealing that it returns live profile data, specifying fields like username, name, bio, verification, and geo-gated post eligibility. It does not discuss rate limits or auth failure behavior, but that is acceptable for this simple check.

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 two sentences with no filler. Purpose and return fields are front-loaded, and the usage instruction is a concise closing note. Every clause earns its place.

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 zero-required-parameter, read-only identity tool, the description covers what it returns, the token context, and when to call it. Even without an output schema, it explicitly lists the key response fields, so the agent has enough to invoke it correctly.

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 description fully documents the only optional parameter, including default behavior and a pointer to list_accounts. The tool description itself adds no parameter-specific detail, so the baseline of 3 applies given 100% schema coverage.

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 names the specific operation ('confirm which Threads profile the current token acts as') and enumerates the returned fields. It clearly differentiates from the sibling list_accounts by focusing on the active token's identity rather than listing all connected profiles.

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 provides an explicit usage cue: 'Use this to check credentials before anything else.' It does not name alternatives or when-not conditions, but the context is clear for a read-only identity verification step.

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