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

Annotations declare readOnly/idempotent safety, but the description adds the costly behavioral facts: slowest tool (~1 minute), AI-generated so the SQL should be verified, an 8-second SQL execution limit, and a known failure mode where per-day subqueries silently return all-null rows. That is well beyond what the annotations convey.

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 identity ('last resort'), then proceeds to cost, scope limits, a specific failure-mode warning, and finally the queryable data boundary. Every sentence carries operational information; nothing is redundant with the title.

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, and the description compensates by stating the return payload (SQL, result rows, short explanation). Combined with the data-scope list and the query-shaping warnings, an agent has everything needed to call this correctly and interpret the result.

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 schema already documents the single 'question' param with an example, so the baseline is 3. The description then adds a real constraint on the parameter's content — keep scope to roughly one region-month because wider aggregates blow the 8-second limit.

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 chain: takes a plain-English question, generates SQL over NEMPulse tables, and returns SQL, rows and an explanation. The opening clause 'Last resort for ad hoc questions the other tools cannot answer' explicitly differentiates it from all ten sibling getters.

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?

Explicit when-to-use ('other tools cannot answer'), when-not (the market analysis tables are unreachable), and alternative-avoidance guidance ('For per-day top-N ... ask for a window function rather than a per-day subquery'). Performance and scope conditions are also given.

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