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

Annotations already declare a safe read-only, idempotent, non-destructive, closed-world profile, but the description adds important operational context: billing is per returned row, limit caps both rows and cost, the exact returned fields are listed, and results are user-generated content to treat as untrusted. This is substantial value beyond the annotations.

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 front-loaded with purpose and usage, then return fields, billing, and trust guidance. Each sentence contributes a distinct, useful fact with no filler or repetition.

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 enumerates the returned columns and notes the untrusted nature of the content. It also covers sorting, matching, cost, and alternatives, so an agent has everything needed to call it correctly and interpret the result.

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%, but the description still adds meaning beyond it: query matching is contains and case-insensitive, results are alphabetically ordered, and limit has a cost implication (billed per returned row; limit caps rows and cost). These details materially affect how an agent sets and interprets both 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?

States a specific verb and resource: search Instagram locations by name or city, case-insensitive, alphabetically. It distinguishes itself from siblings by routing to get_location_info for pks and get_users_by_location for accounts. An agent can identify the operation and its boundary without opening the schema.

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?

Explicitly says when to use it and names two alternatives with their selecting conditions: use this to find location pks for get_location_info, or use get_users_by_location to go straight to accounts posting from a place. No inference required.

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