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

The description adds substantial behavioral detail beyond the read-only annotations: it discloses the mapping of letters to values 1-8, the sacred exlusion of 9, the use of unreduced two-digit compound numbers, and the specific returned components including Cheiro interpretations, planetary ruler, and karmic caution flags. It fully aligns with the annotations and gives the agent a strong mental model of the tool's behavior.

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 contributes distinct information: the Chaldean system, compound number treatment, return contents, and ideal use case. It is front-loaded with the core purpose and minimizes fluff, though the final 'Perfect for' sentence is somewhat marketing-style and could be trimmed without losing essential meaning.

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?

Even without an output schema, the description clearly states what the response will contain: Destiny, Soul Urge, and Personality, each with compound number, root, and Cheiro interpretation, plus planetary ruler and a caution flag. The presence of full schema documentation for all parameters and the read-only annotations makes the definition complete enough for an agent to call it correctly on the first try.

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%, with detailed descriptions for name, lang, and compact. The tool description does not add new parameter-specific semantics beyond what the schema already provides, so the baseline of 3 applies. The description adds context about the reading itself but not directly about parameter formats or meanings.

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 and resource: 'Calculate a complete Chaldean numerology reading for a name.' It clearly distinguishes this tool from siblings by emphasizing the Chaldean mapping, the unreduced compound number, and the combined Destiny, Soul Urge, and Personality outputs. This is not a tautology and leaves no ambiguity about what the tool does.

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 description gives clear contextual use: it is for use cases needing both compound and root layers in one call and for Chaldean rather than other numerology systems. However, it does not explicitly name alternatives or state when not to use this tool, even though several sibling tools cover individual aspects like soul urge or personality. It falls just short of explicit when-when-not guidance.

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