run_prompt_completion

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

Discloses that the tool makes a billable model call, adding context beyond annotations. Annotations already indicate readOnlyHint=false and destructiveHint=false. The description adds value but could mention other side effects like logging.

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?

Two concise sentences: first defines purpose, second provides usage guidelines. No wasted words; front-loaded with essential information.

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 output schema present and extensive parameter descriptions in schema, the description is largely complete. It covers purpose and billing context but could mention error handling or rate limits for a more complete picture.

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%, so baseline is 3. The description adds minimal parameter info beyond the schema, mostly restating that billing metadata is required. No significant enhancement.

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?

Description states 'Execute a prompt against the configured model and return the completion.' This provides a specific verb and resource, and distinguishes from siblings by mentioning render_prompt and validate_completion_metadata.

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?

Explicitly advises to use render_prompt for template checking and validate_completion_metadata when billing fields are uncertain, given the billable nature of the call. Provides clear usage context and alternatives.

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