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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint, so the safety profile is covered. The description adds genuinely useful operational facts not in annotations: the POST endpoint, the 10-credit Tier 1 cost, and the required field set. It does not disclose what the computation returns or how alcocoden weighting is resolved, but with an output schema present that gap is partly covered.

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 bracketed metadata block is compact and front-loads the doctrine reference, but it is schema-like plumbing rather than prose an agent can reason over, and it spends lines restating required params and endpoint path. Nothing is wasted per se, but nothing informs tool selection either.

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 15-parameter, computationally specialized Hellenistic tool with many near-identical siblings, the description omits what the output represents (hyleg/alcocoden years?), how it differs from astroway_dignities_hyleg, and any handling of optional sidereal/house-system parameters. The output schema spares it from explaining return values, but selection-critical context 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 only 33% across 15 parameters, so the description should compensate for undocumented params (city, date, time, name, cosmogram, zodiacType, houseSystem). Instead it merely restates the four required names already listed in the schema's 'required' array, adding no semantics for any optional parameter.

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 the specific technique ('Tetrabiblos III.10 hyleg + alcocoden'), which tells a domain-aware agent this computes the classical longevity doctrine rather than a generic chart. However, it never states a verb like 'compute' and does not differentiate itself from the very similar sibling astroway_dignities_hyleg, so the agent must infer which hyleg tool to use.

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, no prerequisites, and no named alternative despite a near-duplicate sibling (astroway_dignities_hyleg) and a dozen other hellenistic_hand_* tools. The only routing signal is the '[Group: Hellenistic: Hand tradition]' tag, which is categorization rather than guidance.

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