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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds substantive behavioral context the schema cannot: the critical warning that `no_print` is not a zero return and must be carried forward or masked, plus honest disclosure of `classification_limits` where `no_print` conflates illiquidity, suspension, and missing data, and where `pre_listing` can only be asserted with a known listing date.

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 purpose, then usage, then the operational warning, then honesty limits — a sensible priority order with no filler. Given the subtlety of the classification semantics, the length is earned rather than padded.

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 carries the burden of explaining returns and does so: it names the per-day classification values and the `classification_limits` field in the response. An agent has everything needed to call this correctly and interpret the result without guessing.

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%, so baseline is 3, but the description reinforces the semantics that matter most for `days` — that the window is counted in CALENDAR days, not trading days, which is the exact distinction this tool exists to surface. It adds nothing about the symbol/ticker/identifier aliases beyond what the schema already documents.

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 precise verb and resource: for every calendar day in a lookback window, return the reason a price is or is not present, enumerating the six classifications (`traded`, `weekend`, `holiday`, `pre_listing`, `delisted`, `no_print`). This is unmistakably distinct from siblings like get_price_history or get_live_quote, which return prices rather than absence reasons.

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 explicit triggering conditions: 'USE THIS when a price series has gaps' and 'ESPECIALLY before computing returns over a gappy series,' which tells the agent exactly when this tool is the right call. It stops short of naming an alternative tool or stating when not to use it, so it falls just short of a full 5.

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