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

Annotations already declare readOnly, idempotent, non-destructive, open-world, so the safety profile is covered. The description adds genuine behavioral context beyond them: results are point-in-time scoped and carry a flag telling whether the figure was later restated, which materially affects how an agent interprets a row.

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?

A single dense sentence with the resource and the returned detail front-loaded, followed by the use case. Nearly every clause earns its place, though the colon-separated list of return fields makes it slightly packed.

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 a full output schema, rich annotations, and 100% parameter coverage, the description only needs to supply intent and point-in-time semantics, and it does both. It is complete enough to call correctly, missing only explicit sibling routing.

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% and all five parameters are documented in the schema (ticker/CIK/name, decision-date rule, annual/quarterly, concept list, ratios). The description only restates the ratios option and implies period selection, adding little beyond the schema, so the baseline 3 applies.

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 ('Get') and a precise resource/dataset ('what a company had reported as of a date'), then enumerates the returned elements: latest period filed by then, its value, the restatement flag. It is unambiguous but never names or contrasts the nearest siblings (vintages, restatements, history), so the agent must infer the boundary.

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?

'For point-in-time backtests' gives a concrete intended-use context, which is more than implied guidance. It stops short of 5 because it offers no exclusions or explicit routing to alternatives like history or vintages.

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