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

Annotations cover safety (readOnly, idempotent, closed-world), but the description adds substantial traits beyond them: deterministic JPL DE440 engine with no LLM, a per-result meta.result_sha256 for verification, per-call pricing, and the payment mechanisms. That is exactly the behavioral context an agent needs before committing to a paid, deterministic 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?

Four sentences, front-loaded with what is computed and which charts are included, then determinism/hash, then pricing/access. The varga enumeration is long but it is the core payload of the tool and earns its space.

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 no output schema, the description supplies the return shape (per-varga lagna, placements, house table), the verification hash, the engine, and cost/access details. For a 9-parameter paid tool with a nested options object, this leaves nothing an agent needs 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 89%, so the schema already documents date/time/datetime, timezone, time_basis, ambiguous_time, coordinates and the nested options object (ayanamsa, node_type, house_system). The description adds no parameter-level meaning beyond noting Parashara rules, so 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?

States a specific resource (kundli plus all Shodashavarga charts D1..D60) with a clear scope, and explicitly distinguishes itself from the sibling by saying it is 'everything in /vedic/kundli plus' the 16 vargas. An agent can route between kundli and kundli_full 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?

The 'plus' framing implies the selection condition: use this when the full 16-varga set is required, otherwise the cheaper kundli. It also gives practical invocation context (REST endpoint, x402/MPP payment, 3 free calls). However it never states an explicit when-not-to-use or names the alternative outright.

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