send_message

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

No annotations are present, so the description fully disclosures behavioral traits: it is a write operation, rate-limited (1/s per recipient, 10/60s globally), requires signal-cli and SIGNAL_ACCOUNT, and hints at the return structure. This covers all necessary behavioral context.

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 concise, with the main purpose front-loaded, followed by essential rules and constraints in a logical order. Every sentence adds value, and there is no redundant or extraneous content.

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 (4 params, 1 required, mutual exclusivity, rate limits, prerequisites, and output schema), the description covers all necessary aspects: how to specify recipient, error conditions, rate limits, preconditions, and return format. It is fully sufficient for correct agent usage.

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 coverage is 100%, and each parameter has a clear description in the schema (including mutual exclusivity). The tool description restates the exclusivity rule but adds no new semantic details about the parameters themselves beyond what the schema already provides.

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 begins with 'Send a text message via Signal to a direct recipient or group,' which clearly identifies the action and resource. It further distinguishes itself from sibling tools (e.g., read_messages, get_status) by stating it is a write operation that delivers a real message.

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 provides explicit when-to-use guidance: exactly one recipient field must be supplied, and it warns against providing zero or multiple. It also specifies prerequisites (call get_status first) and rate limits, giving clear boundaries for safe invocation.

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