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

Annotations cover the safety profile (readOnly, idempotent, closed-world), and the description adds substantial behavior beyond them: determinism via JPL DE440 with no LLM, a per-result meta.result_sha256 for verification, historical timezone/DST/LMT resolution, the TIME_UNKNOWN warning path, and the $0.15 pay-per-call model with the first 3 calls free.

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?

It is front-loaded with the output inventory and stays information-dense, but the graha/rashi/nakshatra/bhava list is effectively stated twice (once in the first sentence, again in the longer second sentence), which is mild waste for a description of this length.

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 9-parameter, nested-option tool with no output schema, the description adequately covers outputs, determinism, cost, and the hash for verification. It does not address failure modes beyond the TIME_UNKNOWN case or the exact shape of the returned chart, but nothing critical for calling it 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 description coverage is 89%, so the schema already documents nearly every parameter, including the ayanamsa enum, node_type, house_system, time_basis, ambiguous_time, and time-omission behavior. The description's ayanamsa list (Lahiri default; Raman, KP, Yukteshwar, Fagan-Bradley, True Chitrapaksha) largely restates the enum rather than adding syntax or format detail, so the 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?

The description names a specific resource and enumerates its concrete outputs (lagna, 9 grahas with rashi/nakshatra/pada/house/dignity, bhavas, D9 Navamsa), so an agent knows exactly what it produces. However, it never distinguishes itself from the sibling kundli_full, and the D1/D9 vs. 'full' split is left for the agent to guess.

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?

There is no when-to-use guidance: nothing says when to prefer this over kundli_full, natal_chart, or panchang, nor what prerequisites (birth data completeness) are needed. The only operational note is pricing/endpoint, which is not usage guidance.

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