send_message_to_user

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

With no annotations, the description carries full burden. It transparently discloses the dry-run default, the side-effect when dry_run=False, and the return shape (validated status and msgid). It does not mention authentication, rate limits, or failure modes, but for a simple messaging tool this is adequate.

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 well-structured: a one-sentence purpose, a key safety note, a labeled Arg list, and a Returns line. Every sentence earns its place; no fluff or redundancy.

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 simple messaging tool with an output schema, the description covers purpose, parameters, safety mode, and return behavior. It lacks explicit error-case context but is otherwise complete for the tool's complexity.

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 0%, so the description must compensate. It provides clear, meaningful descriptions for all three parameters: user_id, message, and dry_run, exactly matching the schema and adding semantic clarity about validation behavior.

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 'Send an instant message to a user', a specific verb and resource that immediately clarifies the tool's function. No sibling tool has similar messaging purpose, so it is inherently distinguished.

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 clearly states the default dry_run behavior and instructs to set dry_run=False to actually send, providing practical usage guidance. However, it does not explicitly compare to alternatives or state when not to use it, though no alternatives exist.

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