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

Annotations already declare the safe read profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower; the description still adds meaningful semantics: which filing date governs ('as filed by a date'), that the latest period per company is selected rather than a fixed period, that the value reflects the state at that time, and that restatement status is surfaced. It omits error behavior and result ordering, keeping it out of 5 territory.

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?

One front-loaded sentence with the verb, the binding constraints, and the payload described in order; the closing clause on intended use is brief and non-redundant. No filler sentences.

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 an output schema present, return-shape explanation is unnecessary, and annotations carry the safety profile, so the description only needs to cover point-in-time semantics — which it does, including the 50-company ceiling and restatement awareness. Its one gap is not situating the tool against the similarly scoped siblings.

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 the schema already documents as_of, concept, periods, and companies, meaning the baseline is 3. The description reinforces the as-of semantics ('as filed by a date') and the single-measure nature of 'concept', but adds nothing about the annual/quarterly 'periods' option or identifier formats beyond what the schema states.

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 names a specific verb and resource ('Get one measure for up to 50 companies as filed by a date') and even enumerates the three things returned per company (latest period, value, restatement flag). It implicitly separates itself from a time-series sibling like 'history' by stressing a single per-company point, but it never names a sibling explicitly, so it falls short of 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?

Only 'For point-in-time peer and factor work' is offered as usage context. There is no statement of when NOT to use it, and no routing against the close siblings 'known_as_of', 'vintages', 'history', or 'restatements', which a reader could easily confuse with this tool. Usage is implied rather than directed.

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