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

With only readOnlyHint in annotations, the description carries the burden well: it discloses oldest-first ordering, the reporting lag, that as_of is the settlement date rather than today, honest-empty behavior for unpublished tickers, and an explicit DATA_UNAVAILABLE refusal for an unreachable store. It also rules out share counts and days-to-cover, pre-empting wrong assumptions.

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-loaded with the core identity, then return shape, then constraints and caveats. Dense but every clause carries information an agent needs; no filler sentences.

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?

No output schema exists, so the description supplies the return shape ({summary, ticker, count, as_of, trend} and the exact per-point keys) plus edge-case behavior. Nothing needed to invoke 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?

Schema coverage is 100% and already documents points' default and max, so the baseline is 3. The description adds real meaning beyond the schema: 'about one year' for the 26-point cap and that ticker resolves to the FINRA settlement-date series, which clarifies the parameter's semantics.

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+resource+scope: 'FINRA short-interest trend for one ticker', and pins the exact series (biweekly settlement-date short-percent, oldest-first). It is clearly distinguishable from siblings like get_fails_to_deliver or get_institutional_holders.

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?

Gives useful framing that this is a fortnightly snapshot with a reporting lag rather than a live short-float figure, which shapes when it is appropriate. However, it never names an alternative tool or states an explicit when-not condition, leaving the routing decision implicit.

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