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 real value beyond that: a credit cost model ('1 credit per record returned, minimum 2') and the important freshness caveat that results are 'indexed user records, not live profile fetches.'

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 tightly written sentences with zero waste. The core purpose is front-loaded, followed by the cost constraint and the disambiguation note, each earning 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?

With an output schema present, return values needn't be described, and all 17 parameters are documented in the schema. The description covers cost, freshness, and routing, leaving little for an agent to guess. Only the facets sibling relationship is left implicit.

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 rich per-parameter descriptions, so the schema does the heavy lifting. The description only touches page_size indirectly via the cost note and adds no syntax or semantics beyond what the schema provides. Baseline 3 is appropriate.

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 the stored public X (Twitter) user profile dataset using a query and filters') and explicitly distinguishes itself from the item endpoint. An agent can tell it apart from datasets_x_users_item and the live-fetch profile tools 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?

Gives explicit routing: 'use the item endpoint when you have a record ID,' plus practical guidance to keep page_size to what's needed. It does not mention the sibling datasets_x_users_facets, which is a minor gap given the search/facets/item triad.

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