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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds two useful facts beyond that: the credit cost (3 credits) and the concrete set of fields returned, which is meaningful because there is no output schema. It does not cover rate limits or failure 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 short, front-loaded lines: purpose and returns first, id sourcing second, cost last. No filler, no redundancy with the schema.

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 read-only, single-parameter lookup with no output schema, the description compensates by listing the returned fields, and annotations cover the read-only nature. Remaining gaps (pagination, error cases, cost implications in bulk) are minor given the tool's simplicity.

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 coverage is 100% with a single, well-described id parameter, so the baseline would be 3. The description adds value by pointing to /v1/search as the source of valid ids, which helps the agent understand what value belongs in the field rather than just its type.

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 and resource ('Get an Instagram location') and enumerates the returned fields (name, category, address, city, phone, website, post count), which makes the tool's scope concrete. It does not explicitly contrast itself with the closest sibling, instagram_place_posts, so it falls short of a 5.

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 actionable context for obtaining the required argument: 'Find ids with /v1/search.' This tells the agent how to get a valid input rather than leaving it to guess. No explicit when-not-to-use or sibling routing against instagram_place_posts, so not a 5.

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