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

Goes well beyond the annotations (readOnly/destructive/openWorld/idempotent) by disclosing the billing model ($0.005 USDC per call via x402, settled only when a result is returned, 400/4xx/5xx not charged) and the incremental-polling contract via cursor. It also discloses data recency (~last week) and default filtering behavior, which annotations cannot express.

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?

Front-loaded with the questions it answers, then scope, output, filtering, polling, and pricing — a logical order with no filler. It is dense and a little long, but each clause carries distinct operational information, so nothing is wasted.

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 returned fields (stage, filing link, SPAC flag), ordering (newest first), recency window, and pagination via cursor. Together with the cost/settlement details, an agent has everything needed to call and iterate correctly.

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 baseline is 3, but the description adds real meaning: it defines each stage in terms of actual filing forms, clarifies that `since` takes the previous response's cursor, and explains the include_public_companies exclusion rule. This is more than the schema restates, though it does not cover the `via` or `limit` semantics.

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+resource (lists IPO registrations from EDGAR's live feed) and pins the scope precisely: new IPO/SPAC registrations, newest first, with stage labels. It distinguishes itself from the broader sec_list_filings sibling by restricting to IPO/SPAC events and naming the filing types it captures (S-1, F-1, S-11, S-1/A, S-1MEF, 424B4).

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?

Usage is well-signaled through concrete triggering questions ('Who filed for an IPO this week?', 'Any new SPACs?') and operational guidance (poll with `since` = previous cursor; filter by stage or SPACs). It clearly states what is excluded (resale/follow-ons unless include_public_companies) but never names a sibling tool as the alternative, so it stops short of an explicit when-not/alternative routing.

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