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

With readOnlyHint=true, the tool is known to be read-only. The description adds valuable behavioral context: it discloses that AMD and AVGO get the full sheet for free, other tickers are paid with specific terms, and uncovered tickers return not_covered. This goes beyond the annotation, though it doesn't detail the exact return structure or URL format.

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 description is concise but information-dense, covering content, layout, scaling, free vs paid, and error handling in a few sentences. It is front-loaded with the core purpose and uses clear formatting.

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?

Given the simple parameter set (one ticker), high schema coverage, and read-only annotation, the description adequately explains what the tool does, the different tiers of access, and what happens for uncovered tickers. No output schema exists, but the description provides enough context for an agent to call it 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%, and the description reiterates the ticker parameter with examples of free and paid tickers, which adds slight value beyond the schema. Since the schema already describes the parameter, a baseline of 3 is appropriate.

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 clearly states the tool provides a line-item trajectory sheet with three fiscal years of income statement, balance sheet, and cash flow lines for one company. It distinguishes itself from siblings by emphasizing the standard layout and scaling, and mentions the free sheets for AMD and AVGO.

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?

The description explains when to use the tool (for any covered ticker) and gives specific examples of free vs paid tickers, but it does not explicitly mention alternatives or when not to use this tool. It implies usage through the coverage check but could be more explicit.

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