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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior. The description adds useful operational context the annotations do not carry: the POST endpoint and the 20-credit Tier 2 cost. It says nothing about failure modes, validation, or response behavior for this computation.

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?

Very compact and front-loaded: purpose first, then bracketed metadata blocks that are easy to scan. Every element earns its place, though the tags are terse enough that some context is arguably left out rather than trimmed.

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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. However, for a 15-parameter chart-computation tool the description is thin: it gives no framing on ayanamsa/house-system selection or the meaning of the D16 division, leaving the agent to work entirely from schema descriptions that cover only a third of the parameters.

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 only 33%, and the description's only parameter content is the list of required fields (date, time, latitude, longitude), which merely repeats the schema's required array. None of the 11 optional parameters (ayanamsa, houseSystem, zodiacType, precision, fields, etc.) receive any added meaning from the description, so it does not compensate for the coverage gap.

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 (the Shodasamsa / D16 divisional chart) and adds the traditional significations (vehicles, comforts, conveyances), which tells an agent what the chart is for. It has no verb, but the D16 designation implicitly separates it from the D1/D2/D9/D20 siblings in the same family.

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 parenthetical 'vehicles, comforts, conveyances' implies the kinds of questions this chart answers, and the cost line signals a Tier 2 spend, but there is no explicit statement of when to pick D16 over another varga or when not to use it. Usage is inferable rather than stated.

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