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

Annotations cover the safety profile (read-only, non-destructive, closed-world), so the bar is lower, yet the description still adds real behavior: newest-first ordering, cross-stage threading via file number, the historical coverage boundary, and the exact {data, total, limit, offset} response envelope. It does not mention auth requirements or throttling, so not a 5.

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?

Four front-loaded sentences, opening with verb+resource and ordering, then enrichment, then coverage caveat, then return shape. Every sentence carries information an agent would otherwise have to discover empirically; no boilerplate or 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?

With no output schema, the description compensates by describing the envelope and field-level content of issuer objects, and all 8 parameters are documented in the schema. Remaining gaps are minor: no mention of permission/auth requirements and no explicit contrast with the detail-oriented get_registration_event sibling.

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 88%, so the baseline is 3, but the description adds semantics the schema lacks: file_number is described as following one offering across lifecycle stages, the stage filter is mapped to concrete filing forms, and the issuer object's fields (SIC code, state of incorporation, former names) are surfaced. It does not explain since/until interplay beyond what the schema already notes.

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?

Specific verb+resource with enumerated scope: 'List S-1/F-1 registration lifecycle events' covering registration statements, amendments, EFFECT notices, and 424B1/424B4 prospectuses. It is far more precise than a generic 'get filings'. However, it never distinguishes itself from the singular sibling get_registration_event or from get_corporate_events, so the sibling-differentiation element of a 5 is missing.

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 clear operative context: results are ordered newest first, records are threaded by SEC file number, and coverage is 'live-forward since 2026-08-01', which tells the agent exactly which queries will return data. It stops short of naming an alternative tool or stating when-not to use it, so no explicit exclusion guidance.

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