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

Annotations already mark the tool read-only, idempotent, and non-destructive, and the description adds substantial non-obvious behavior: dynamic credit cost '65-280 per page, charged even when the result set is empty and on a 504 timeout,' plan history limits, and the Pro plan requirement. It also clearly discloses what is omitted from results.

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 dense but logically front-loaded: purpose and return behavior come first, followed by date semantics, pagination, costs, and plan requirements. Every sentence carries useful information, though the trailing endpoint and documentation reference add modest redundancy.

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 10-parameter tool with no output schema, the definition covers return semantics, omissions, date behavior, pagination bounds, plan/history limits, credit costs including empty-result and timeout charges, and sibling tools for setup and full filing retrieval. Nothing essential for an agent to call it correctly is missing.

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%, so the schema already documents every parameter; the description still adds meaning by stating that date parameters filter filing_date and clarifying that as_of_date acts as an end bound with no start. It also ties items to list_event_types, though pagination details partly duplicate the schema.

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?

Opens with a specific verb and resource: 'Screen corporate events across companies and filing dates,' and then defines the result shape (filings with matching section summaries, source links, amendment status, newest first). It also distinguishes itself from siblings by pointing to list_event_types for Item codes and get_event_filing for complete filings.

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 names alternatives and when they apply: 'Use list_event_types to choose Item codes, and get_event_filing with a returned id for the complete filing.' It also signals when the screener is insufficient by noting that original text and amendment history are not included.

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