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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuine behavioral context beyond that: it explains the fiscal-calendar semantics ('Fiscal years are the company's own' with NVIDIA/Apple examples) and the 52/53-week-year nuance, which materially affects how an agent interprets returned periods. It stops short of stating return format or ordering, but this is useful added context.

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?

The scope statement is correctly front-loaded, but the body is a single semicolon-chained run-on enumerating many fields with no visual structuring, which is hard to scan. The content largely earns its place given the absence of an output schema, but the packaging is dense and monotone.

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 and no annotation detail on returns, the description carries the full burden and does so: it enumerates the period fields, the YTD/TTM blocks, the fiscal year end, the week-based-year flag, and the published-records list with their permanent URLs. Combined with the fiscal-calendar explanation, an agent has what it needs to use and interpret the result.

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?

One parameter at 100% schema coverage, so the schema already documents the ticker and its case-insensitivity with examples. The description adds no parameter-level detail beyond that, which is the expected baseline 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?

Opens with a concrete scope statement ('How far back the data goes for one company: every fiscal year and every quarter'), which is a specific resource with clear framing, and enumerates the payload (period dates, source form/accession, YTD/TTM blocks, fiscal year end). It does not explicitly differentiate itself from near neighbors like get_filings or get_company, which also touch filings and company metadata, so 4 rather than 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?

There is no when-to-use guidance, no prerequisites, and no mention of alternative tools such as get_filings or list_upcoming_filings. An agent must infer that this is the tool for enumerating reporting periods from the name alone.

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