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

The readOnlyHint annotation already declares this a safe read, so the bar is lower. The description adds that results are periodized and cites the underlying API endpoint, but says nothing about return shape, pagination, or auth needs beyond what annotations cover.

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?

Three short sentences, front-loaded with the core purpose and zero padding. The API endpoint citation is mildly redundant but potentially useful for an agent reasoning about the request.

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 simple read-only retrieval tool with full schema coverage and a readOnlyHint annotation, the description covers purpose, required params, and scoping. Nothing critical is missing, though a note on what the periods contain would round it out.

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 all four parameters are already documented, including the 1-12 bounds. The description reinforces that periodLength and periodsToCompare are both required, but adds no syntax or format detail 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 resource (profit & loss / income statement) and adds the 'broken into periods' detail. The resource name inherently distinguishes it from siblings like get_balance_sheet and get_cash_flow_statement, though it doesn't explicitly name them.

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 resource (financial statement retrieval) but the description gives no explicit when-to-use, when-not, or sibling routing. It only adds the constraint that two params are required, which is a setup note rather than usage guidance.

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