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

Annotations only cover the read-only/idempotent profile, so the description carries real extra weight: determinism source (JPL DE440, no LLM), the meta.result_sha256 provenance field, the $0.50 per-call price, the REST/x402/MPP access path, and the 'first 3 free' quota. These are exactly the operational facts an agent needs before invoking a paid, hash-verifiable tool.

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?

Two sentences, front-loaded with the content summary before the billing and endpoint details. It is dense but every clause (content scope, determinism, hash, price, endpoint, free tier) carries information, so the length is justified rather than padded.

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, 10 parameters, and nested options, the description supplies the key return-side signals (dasha depth levels, on_date activity, result_sha256) plus cost and access mechanics. It does not describe output shape beyond the hash, but for a deterministic bundled report this is close to sufficient.

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 90%, so the schema already documents date/time/on_date/options and their enums. The description adds only a marginal hint about on_date ('running periods with on_date') and the 2-level dasha depth, so the baseline 3 applies rather than a bonus.

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?

The first sentence names the specific composite content (Kundli, Vimshottari dashas, doshas, janma panchang) and frames the tool as a bundled dossier for one person. It explicitly enumerates the sibling endpoints it aggregates (/vedic/kundli, /vedic/dashas, /vedic/doshas, panchang), so an agent can distinguish it from the individual sibling tools without opening a 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 description makes the core selection logic clear: 'in one call' versus the enumerated per-domain endpoints, which tells the agent to prefer this when it wants the whole dossier. It stops short of an explicit when-not or a direct contrast with the similarly named sibling kundli_full, leaving that overlap to inference.

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