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

Annotations already establish readOnly, idempotent, and non-destructive behavior, so the description's job is to add context beyond those. It does: it discloses that only the sign-modality method is represented, that 'overall_assessment' is not a reconciled verdict, and how 'checks_summary' and the check lists are structured. 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?

The description is longer than average, but every sentence earns its place by explaining a distinct part of the output that would otherwise be opaque given no output schema. It is front-loaded with the core purpose and the key caveat ('does not issue a longevity verdict') before diving into field-level details.

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 carries the full burden of explaining the response, and it does so thoroughly: it covers 'overall_assessment' semantics and its category codes, 'method_note', 'checks_summary', each set of check combinations, and the calculation basis fields. Nothing essential about the return value is left unexplained.

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 100%, so the schema already documents all seven parameters in detail. The description focuses on the output structure rather than the input parameters, which is acceptable at the baseline. It does not add parameter-specific meaning, but it does not need to given full schema coverage.

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 opens with a specific verb-resource pair: 'Return the chart's classical Ayurdaya (longevity) computations.' It immediately distinguishes the tool's scope by stating it does not issue a verdict but exposes classical signals side-by-side, which clearly differentiates it from general horoscope and yoga tools among the siblings.

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 provides clear context for when this tool is appropriate: for astrologer interpretation of classical longevity signals. The explicit caveat that it 'does not issue a longevity verdict' and that 'method_note' is not a reconciled verdict tells the agent when not to treat this as a definitive answer. It does not name alternative sibling tools, so it stops short of a fully explicit when-to-use-vs-alternatives statement.

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