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

Adds substantial context beyond the annotations: deterministic computation (JPL DE440, no LLM), a verifiable meta.result_sha256 on every result, and commercial terms ($0.10/call, x402/MPP payment, 3 free calls) with the REST endpoint. This tells the agent about cost, payment requirements, and result verifiability, none of which the readOnly/idempotent annotations convey. No contradiction with annotations.

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?

Three sentences, front-loaded with the core purpose and return contents, then determinism/hash, then pricing. Every sentence carries information, though the REST URL and payment-mechanism detail make the tail denser than necessary for tool selection.

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 10 parameters, a nested options object, no output schema, and 2 required inputs, the description covers the essential capabilities and even points to result verifiability via sha256. It stops short of describing output structure or how the running-period list is formatted, but for a no-output-schema tool this is close to complete.

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/datetime, on_date, depth levels, and the option enums. The description restates the depth concept ('sub-periods down to 4 levels') and the on_date behavior, adding mild reinforcement but no syntax or format detail beyond the schema. Baseline 3 applies when structured fields carry the load.

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?

Names a specific resource (Vimshottari maha/antar/pratyantar periods) and enumerates exactly what is returned: birth balance, all 9 mahadashas with sub-periods to 4 levels, and periods running on a date. An agent can immediately distinguish this from siblings like kundli, nakshatras, or panchang. The scope is concrete and unambiguous.

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?

It implies usage via 'with on_date' for the running-periods case, and the free-tier/pricing note hints at call economics, but it never states when to pick this over kundli, kundli_full, or nakshatras, nor any prerequisite conditions. Guidance is inferable rather than explicit.

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