send_message

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the Business plan requirement (useful for auth/access context) but doesn't describe other traits like rate limits, error handling, whether messages are sent immediately or queued, or what happens if mediaUrls fail. For a mutation tool with zero annotation coverage, this leaves significant gaps.

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 appropriately sized with two sentences that are front-loaded with key information (action, platforms, media support, requirement). It avoids redundancy, though it could be slightly more structured by separating functional details from constraints.

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?

Given the tool's complexity (mutation with 5 parameters, no annotations, no output schema), the description is minimally adequate. It covers the core purpose and a key constraint (Business plan), but lacks details on behavioral traits, output format, or error handling, which are important for a mutation tool. It meets basic needs but has clear gaps.

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 the schema already documents all 5 parameters thoroughly. The description adds minimal value beyond the schema—it mentions text/media support and platforms, which aligns with the schema's 'platform' enum and 'mediaUrls' parameter, but doesn't provide additional syntax, format, or usage details. Baseline 3 is appropriate when schema does the heavy lifting.

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 action ('send a direct message') and resource ('on a social platform'), specifying support for text/media and platforms (Facebook, Instagram, X/Twitter). It distinguishes from siblings like 'create_post' (public posts) and 'get_messages' (read operations), but could be more explicit about the 'direct message' vs. other message types.

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 implies usage for direct messaging across specific platforms and mentions a Business plan requirement, providing some context. However, it lacks explicit guidance on when to use this tool vs. alternatives like 'create_post' for public content or 'post_comment' for comments, and doesn't specify exclusions or edge cases.

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