msg_send

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 does add value by revealing that the tool supports deduplication and threading, which are non-obvious behaviors. However, it does not disclose other important traits such as delivery guarantees, error behavior, or whether the operation is asynchronous. This is adequate but incomplete.

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 a single, well-structured sentence that front-loads the main action, then adds the two key feature mentions. Every word earns its place, with no redundancy or unnecessary detail.

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 tool with 7 parameters, no output schema, and no annotations, the description is functional but lacks some completeness. It covers the core purpose and highlights important features, but does not mention return values, error handling, or prerequisites like recipient validation. This is a minor gap for a simple send operation, but the absence of any output schema info prevents a higher score.

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 baseline is 3. The description adds some context by associating dedup_key and thread_id with the mentioned deduplication/threading features, but the schema already describes these parameters clearly. No additional parameter details are provided beyond what the schema offers.

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's function: 'Send a message to another agent.' This is a specific verb+resource combination that distinguishes it from siblings like msg_read_inbox (reading) and msg_broadcast (sending to many). Mention of deduplication and threading further clarifies unique capabilities.

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 context by specifying 'to another agent,' which sets it apart from broadcast or read tools. It does not explicitly name alternatives or exclusion scenarios, but the context is clear and the highlighted dedup/threading features provide guidance on when to use these capabilities. No explicit 'when not to use' is given, so it's not a 5.

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