Create message (Anthropic-compatible)

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

Discloses authentication method and support for vision/streaming beyond annotations. However, does not describe response format, side effects of repeated calls, or rate limits, which would add further value.

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?

Three sentences covering purpose, capabilities, and authentication with no redundancy. Every sentence adds value, making it highly efficient.

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?

Adequate for a complex tool with 14 parameters and no output schema, but missing details on response format, error handling, and how to construct nested inputs like messages and tools. More context would improve completeness.

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?

With 71% schema coverage, descriptions cover most parameters. The description adds context about vision and streaming, hinting at relevant parameters, but does not explain all complex nested object structures in detail.

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?

Clearly states it creates an Anthropic-compatible message using native format. Differentiates from siblings like create_chat_completion (OpenAI) and create_gemini_content by specifying Anthropic's format and Claude models.

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?

Implies usage for Anthropic models with vision and streaming, but does not explicitly state when to use this tool over alternatives or provide exclusions. Lacks explicit 'when-not-to-use' guidance.

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