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

Annotations already establish readOnly/idempotent/non-destructive/openWorld=false, so safety is covered. The description adds materially beyond them: an API-key requirement, the row grain (per launch per UTC observation day), the live vs catch-up observation model, and offset-based paging. It omits rate limits and any note on response size or ordering.

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 auth requirement, then the row semantics, then filters, then paging. The middle sentence is a long run-on clause chain, but nearly every clause carries distinct information and nothing is redundant filler.

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 an 8-parameter read tool with no output schema and no required params, the description does substantial work: it defines the row grain, enumerates the returned fields, lists the filterable dimensions, and states the paging mechanism. The remaining gap is the unresolved routing versus launch_slips.

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%, so every parameter is already documented in the schema; baseline is 3. The description's filter list ('launch, provider, rocket, observation, kind and day') merely mirrors the schema and is slightly looser than reality, since it says 'day' where the schema's parameter ('since') filters on-or-after.

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 resource and its exact contents: 'every launch date change our ledger holds... one row per launch per UTC observation day,' and enumerates the observation fields it carries. This is far more than a restatement of the name. It does not, however, crisply separate itself from siblings launch_slips or launch_on_time_record, so it stops short of 5.

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 a real prerequisite ('Needs a SpaceNexus API key (a free key is enough)') and names the related free dataset. But the relationship is left ambiguous – 'The same rows as the free launch-slips dataset' tells an agent the rows match without saying which tool to pick or when. No explicit when-not guidance.

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