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

Goes well beyond the annotations (which already cover read-only/idempotent/non-destructive) by disclosing the 1,000-point cap with its error code, per-call credit pricing, that only successful calls are charged, that a sandbox key returns a fixed free sample, and that results are deterministic. This is exactly the operational context an agent needs before committing to a billable call.

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 correctly and the critical cap appears early, but the pricing sentence is essentially duplicated ('**Price: 1 credit per started 100 points** (a 365-point daily table costs 4)' followed by 'Cost: 1 credit per started 100 points'). That redundancy wastes space in an otherwise tight definition.

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 an output schema present, return values need not be described, and the description covers the operational essentials: caps, cost, determinism, defaults, and an example call. The only gap is that it never routes the agent away from get_ephemeris_positions for single-instant queries.

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 the schema carries the parameter detail and the baseline is 3. The description adds value with a concrete example argument object and by tying stepMinutes to the 1,000-point ceiling, which helps the agent reason about the interaction between the two required params.

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 ('Positions over a range'), defines the sampling cadence ('from start to end inclusive every stepMinutes'), and names its audience ('transit tables and station finding'). It implicitly distinguishes itself from get_ephemeris_positions by being range-based, but never names that sibling explicitly, so the differentiation is left to inference.

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 use context ('for transit tables and station finding') but no when-not guidance and no reference to alternatives like get_ephemeris_positions. An agent can infer this is the multi-point variant, but the description never says what selects it over its siblings.

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