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

The description says 'Get an Instagram profile,' which implies a read-only retrieval, while the annotations explicitly set readOnlyHint=false. This is a direct contradiction. The description also omits any auth, rate-limit, or side-effect context.

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?

A single front-loaded sentence with no wasted words. It states the resource and the key returned data immediately.

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?

The description covers the returned profile data, and an output schema exists, so return values need not be explained. However, with zero required parameters and both identifiers nullable, it should clarify that the caller must supply a username or user_id. That gap matters for correct 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 description coverage is 100%, and both optional parameters (user_id and username) are already documented in the schema. The description adds no parameter-level meaning, such as whether one identifier is required or preferred, so the baseline of 3 applies.

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 states a specific verb and resource: 'Get an Instagram profile.' It also names the fields returned (bio, follower counts, account metadata), which clearly differentiates it from media-focused siblings like instagram_media.

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 retrieval intent is implied by 'Get an Instagram profile,' but there is no explicit guidance on when to use this versus instagram_media or other profile tools. No prerequisites or exclusions are stated.

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