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

Annotations already establish this as a read-only, idempotent, closed-world operation, so the bar is lower. The description adds meaningful methodological context — the 1-day and 7-day windows measured against the first firm date — which tells the agent how the numbers are derived and why results may differ from raw slip data.

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?

One dense sentence, front-loaded with the core metric and its exact thresholds, then the aggregate measures, then the grouping options. No filler or restatement of 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?

For a no-required-parameter aggregation tool with no output schema, the description defines the metrics well enough to interpret results. It stops short of describing the returned shape (group label, counts, sample size), which would help since no output schema exists, but nothing needed to invoke 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 description coverage is 100% — name, limit, and group_by are all documented in-schema, including the enum values and default. The description restates the grouping dimension but adds no filtering syntax or semantic nuance beyond the schema, so the baseline 3 applies.

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?

The description states a specific computed resource (on-time launch record) with exact metric definitions: share lifted off within 1 day and 7 days of the first firm date, plus mean/median delay and grouping dimension. This distinguishes it clearly from siblings like launch_slips (individual slips) and next_launches (upcoming).

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?

Usage is implied by the metric definition and the group_by parameter, but the description never states when to prefer this over launch_slips or launch_ledger_record, nor any preconditions. An agent can infer the niche but must do the routing work itself.

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