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

With only readOnlyHint available, the description carries the rest of the burden and does so: unit convention (millions, not raw dollars), the as-of-filing-date caveat with the risk that the current-year bucket is already repaid, refusal_reason/refusal_note on empty results, and the Researcher-tier requirement. These are exactly the non-obvious traits an agent needs before quoting numbers.

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?

Front-loads what the tool is and its units caveat, then layers validation, refusal, alternative-tool, source and tier notes. The field enumeration earns its place because there is no output schema to document the return shape.

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 single-parameter read tool with no output schema, the description covers return shape, units, temporal caveat, refusal behavior, prerequisite tier, and a sibling alternative. Nothing needed to call or interpret it correctly is missing.

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?

Only one parameter (ticker) with 100% schema description coverage, so the schema already documents the input fully. The description adds no syntax or format detail beyond the schema, making the baseline 3 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?

States a specific verb and resource ('Forward debt maturity ladder parsed from the latest 10-K/20-F footnote'), including the exact source document. It explicitly distinguishes itself from get_capital_allocation, so an agent can separate it from the closest sibling without opening a schema.

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?

Names the alternative and the condition that selects it ('For historical issuance/repayment use get_capital_allocation'), and instructs the agent to consult `validation` before quoting a total. This is explicit routing rather than implied usage.

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