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

Goes well beyond the read-only/idempotent annotations: discloses the 1,000-point hard cap and the too_many_points failure, the credit pricing model per started 100 points, that only successful calls are charged, that sandbox keys return fixed samples, and that results are deterministic. These are exactly the operational facts an agent needs before spending credits.

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 trigger condition in the first clause, then layers scope, limits, cost, and an example in descending order of importance. The minor restatement of 'transit table/station finding' is tolerable and every other sentence carries new information.

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 available, the description doesn't need to explain return values, and it closes the remaining gaps an agent would hit: rate/point ceiling, error name, credit cost, and determinism. Zodiac and ayanamsa defaults are fully covered by the schema.

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; the description earns an extra point by tying stepMinutes to output density ('every stepMinutes', '365-point daily table') and by supplying a worked example with real body names and stepMinutes=1440, which anchors the units and array format.

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 (planetary positions) with an explicit scope qualifier ('across a range of dates') and concrete ends (transit table, sign changes, stations). This implicitly separates it from get_ephemeris_positions, though it never names that sibling outright.

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 concrete situations that should trigger the tool — building a transit table, finding when a planet changes sign or stations. It stops short of explicit exclusions such as 'for a single moment use get_ephemeris_positions instead', so the agent must infer the boundary from the sibling list.

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