Moon-Phase Sleep Tips

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is fully covered. The description adds the cost (10 credits, Tier 1) and the POST endpoint, which are genuinely useful beyond annotations, but says nothing about response shape or how the date maps to a phase. With an output schema present, that gap is tolerable.

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 prose portion is a single tight sentence, front-loaded with the purpose, followed by the prerequisite hint. The bracketed metadata block is boilerplate rather than descriptive prose but does not bloat the core message.

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 one-parameter read tool with full annotations and an output schema, this is close to adequate: purpose, prerequisite, and cost are all present. What is missing is the key semantic link — that the date determines which moon phase's sleep tips are returned — leaving the agent to infer the contract.

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 0%, so the description must carry the burden of explaining the single required 'date' parameter. It only repeats 'Required: date' — the same fact the schema already enforces — and adds nothing about whether the date is interpreted as today's phase, the user's local day, or a target night. The YYYY-MM-DD pattern exists only in the schema as a regex.

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?

States a specific verb and resource: 'Sleep recommendations per moon phase', which is more specific than the title alone. It is distinguishable from the generic wellness siblings (diet, exercise, herbs) by its moon-phase framing, though it never explicitly contrasts with astroway_calendar_moon_phase which supplies the same underlying signal.

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 'Pair with /sun-times to find current phase' line implies a prerequisite lookup step, but it names a path rather than a concrete sibling tool and gives no condition for when to use this versus other wellness endpoints. Usage is implied rather than stated.

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