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

Far exceeds the readOnlyHint annotation: it discloses no network call, sub-millisecond fixed-key envelope, all price fields null, the retired status object, and nuanced error semantics distinguishing malformed input ('CUSIP must be at least 6 characters') from the retirement note. This is unusually rich behavioral disclosure.

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 the most critical fact (RETIRED) and the actionable alternative. It is dense and lists all 23 envelope keys, which is verbose but justified as a stable-contract guarantee. Slightly heavy but no padding.

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, the description fully specifies the return shape (fixed-key envelope, null prices, status object) and error behavior, so an agent knows exactly what calling it yields. Complete for a retired tool.

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 single cusip param is documented there (9-char, e.g. 037833AK6). The description adds meaning beyond the schema by explaining the minimum-length validation error path. Baseline 3 with a small increment for the validation detail.

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 retired verb+resource (single-bond trade detail by CUSIP over FINRA TRACE), notes it is RETIRED with a date, and explicitly names the two sibling replacements. An agent can immediately tell this tool is defunct and where to go instead.

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?

Explicitly routes the caller: 'Use ol_bond_directory_screen ... or get_debt_maturities for one issuer's own maturity schedule,' and clarifies that no CUSIP can be priced here. The when-not-to-use condition is stated outright.

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