Call the Hand

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

It discloses non-idempotency, mutation of shared state (debt row or Hand deck), priority ordering for owed debt, and the exact return shape. Annotations only hint at read-only/destructive status, but the description goes well beyond them, adding meaningful behavioral context without contradicting anything.

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 minimal but every sentence earns its place, covering the invocation rule, procedural details, narrative requirement, alternative, side effects, and return contract. It is front-loaded with the trigger condition and structured into logical paragraphs.

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 side-effectful tool with an empty schema and no output schema, the description is remarkably complete. It explains the trigger, source selection rule, debt precedence, intrusion requirement, consequences, non-idempotent behavior, and return fields—nothing important is left unspecified.

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?

There are zero parameters, so the schema cannot carry meaning. The description explicitly notes 'Takes no parameters,' which resolves any ambiguity and matches the empty input schema. A baseline of 4 is appropriate for a no-param tool.

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 clearly states the tool triggers the Called Hand when an omen lands doubles, with a specific triggering condition and relationship to cast_omen. It distinguishes this from defiance and other sibling tools by explaining its exact role in the flow.

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 explicitly states when to call it ('immediately whenever cast_omen returns doubles=True'), that it is not for the player to invoke, and points to defy_roll as the alternative for fighting the landed fortune. This provides strong usage guidance with clear exclusions.

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