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

Annotations declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable behavior: newest-first ordering, event-type inclusion, file-number threading, issuer object fields, coverage start date, and a {data, total, limit, offset} envelope expectation. No contradictions with 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?

Three sentences, front-loaded with the core action and ordering, then lifecycle stage details, then clear scope/coverage and envelope shape. Every sentence earns its place without 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 read-only list endpoint with 88% schema coverage and no output schema, the description covers the essential behaviors: ordering, event types, threading, issuer fields, date coverage, and pagination envelope. It could mention default limit/pagination nuances, but the schema already carries limit/offset defaults, so the description is largely complete for an agent selecting and invoking the tool.

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 description coverage is 88%, so the schema already documents most parameter meanings. The description adds context that 'stage' corresponds to lifecycle stages and that file_number 'follows one offering across stages', which enriches those parameters, but most parameter meaning still comes from the schema. A 3 baseline 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?

The description states a specific verb (List), a clear resource (S-1/F-1 registration lifecycle events), and distinctive details (newest first, threaded by SEC file number, types of events, issuer attributes, coverage start date, response envelope). It clearly distinguishes this tool from siblings like get_registration_event and get_corporate_events by describing the broad lifecycle-oriented scope.

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?

The description includes explicit selection signals: it lists the event types covered, states coverage is live-forward since 2026-08-01, and names the file-number threading concept. It does not explicitly name sibling alternatives or when not to use them, but the detail makes the intended use clear. The since/until fixed-window phrasing also gives useful when-to-use guidance.

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