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

Goes well past the annotations (which only cover readOnly/idempotent/no-destruction) by disclosing determinism with no LLM call, cost of 12 credits with charging rules, a free sandbox key, and the caveat that uncertain birth times change the reading. It also enumerates the substantive outputs (verdict, marital promise, Manglik reckoning, timing window, synastry), which is the behavioral context an agent needs to set expectations.

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 when-to-use and the sibling routing, then layers detail efficiently. It loses a point for redundancy: determinism is asserted twice ('no language model is called' / 'the same input always gives the same answer'), which could be a single clause.

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 nested-input, paid, deterministic tool with an output schema, the description covers trigger, alternative, inputs shape, cost, determinism, and the limits of accuracy under unknown birth time. 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 coverage is already 100%, so the baseline would be 3, but the description adds the structural note that each partner is a BirthData object plus optional name/gender and supplies a complete worked example argument object. The referenceDateIso anchoring is left to the schema, which is a minor omission given the otherwise strong supplementation.

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 and resource ('reads both charts together for marriage') and pins the scope as the full reading rather than a bare score. It explicitly distinguishes itself from the sibling get_guna_milan, so an agent can route without opening either schema.

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?

Opens with the trigger condition ('when the user asks whether two people are a good match for marriage and wants the full reading') and names the alternative plus the condition that selects it ('fast 36-point score with Manglik alone, use get_guna_milan'). Nothing is left to inference.

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