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

Annotations already declare the full safety profile (readOnly, idempotent, non-destructive, closed-world), so the description carries a lower burden. It usefully adds cost (10 credits, Tier 1), the endpoint, and the tradition (Cheiro), which are genuine facts not present in structured fields, but says nothing about response content or limits.

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?

It is very short and front-loads the topical anchor before the bracketed metadata lines. Nothing is padded, though the fragmentary first line is terse to the point of incompleteness rather than waste.

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 an output schema present and zero required parameters, the description need not explain returns or inputs extensively. Still, it is thin for a topically distinct reading tool — an agent gets a domain label but no confirmation of what the reading produces or when it is the right line to request.

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% and both parameters (fields, precision) are fully documented in the schema, including the compact-mode examples. The description adds no parameter meaning, so the baseline 3 applies with the schema doing all the work.

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 'Emotional life, romance' names the topical domain and does loosely differentiate the heart line from siblings like head_line (intellect) or fate_line (career). However, it never states the action — it doesn't say it generates or interprets a palmistry heart-line reading, leaving the verb implied by the name/endpoint. That makes the purpose understandable but under-specified.

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 exclusions, and no routing to alternatives — it doesn't tell the agent to pick this over head_line, life_line, or marriage_line. The group and endpoint metadata hint at context but supply no selection criteria.

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