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

Annotations already declare read-only, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds real behavioral value the annotations do not: newest-accepted-first ordering, the 40-filing cap, values as first reported rather than restated, and the inclusion of EDGAR acceptance time and filing link. It omits pagination behavior (offset) and any rate/limit caveats.

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, no filler, with the resource and ordering constraint front-loaded before the as_of clarification. Dense but every clause carries information; slightly over-packed into one long opening sentence rather than being maximally scannable.

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 query tool with a fully documented 8-parameter schema, strong annotations, and no output schema, the description covers what an agent needs: the filing scope, the first-reported semantics, the point-in-time meaning of as_of, and the ordering. Nothing about calling 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 description coverage is 100%, so every parameter including as_of, limit, offset, form, fields and amendments is already documented in the schema. The description restates the as_of constraint and the 40-filing cap but adds no syntax, format, or default detail beyond what the schema provides. Baseline 3 is correct when the schema does the heavy lifting.

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?

Names a specific resource (10-K/10-Q/20-F/40-F filings with revenue, profit, EPS, cash, debt, cash flow, margins) and a specific behavioral twist (metrics 'as each filing first reported them', point-in-time via as_of). An agent knows exactly what it returns. It does not, however, contrast itself against the siblings metric_history or snapshot_as_of, which is the only thing keeping it from a 5.

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 implied by the phrase 'as_of = only filings accepted by then', which tells the agent the point-in-time semantics, but there is no explicit statement of when to choose this over metric_history or snapshot_as_of, and no stated exclusions or prerequisites. Adequate but leaves the routing decision to inference.

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