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

Annotations already declare readOnly, idempotent, non-destructive. Description adds that it builds noise-reduced URLs and quality scores, and does not scrape or collect posts. This is useful but modest; no mention of response format or authorization, which output schema partially covers.

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?

Two sentences, each earning its place. First sentence states purpose and usage scope; second sentence clarifies exclusions. No redundancy or unnecessary detail.

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 only one parameter, high schema coverage, and an output schema, the description is fully adequate. It covers purpose, usage boundaries, and behavioral constraints. No missing information for a tool of this complexity.

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 single parameter 'intent' is fully described in the schema with an example. Description enriches by listing specific intent categories (complaints, bug reports, etc.), adding meaning beyond the schema's generic 'research goal'.

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?

Clearly states it's for specialized X (Twitter) research planning, lists specific use cases (complaints, bug reports, etc.), and distinguishes from general web search and scraping. The verb 'search_plan' combined with 'builds URLs and quality scores' defines a specific resource and action.

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 limits usage to X research planning and provides examples of when to use. Also clarifies what it is not (not general web search, not scraping). However, it does not explicitly compare to sibling tools (build_handoff, filter_signals), which could help further.

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