Send Message to Contact

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

Annotations declare readOnly=false, openWorld=true, idempotent=false, destructive=false, so the safety profile is largely covered. The description adds the genuinely useful operational constraint of the 24-hour session window, which annotations cannot express. It stops short of describing delivery/failure behavior or rate limits.

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 short sentences, front-loaded with the action, then the constraint, then the fallback tool. Every sentence carries distinct, non-redundant information.

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?

With no output schema, the description need not explain returns, and the annotations cover mutation safety. The critical eligibility rule is disclosed, making this nearly complete, though a note on failure behavior inside/outside the window would close the remaining gap.

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% and the nested message object's type enum, text, and url fields are all documented in the schema, so the baseline is 3. The description adds no parameter-level detail (e.g. which message types consume the window) 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?

States a specific verb (send) and resource (message to a contact), and explicitly distinguishes itself from sibling sendpulse_send_template by naming it. An agent can pick between them without opening either schema.

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?

Gives an explicit eligibility condition (only within the 24-hour messaging window after the contact last messaged) and names the alternative tool plus the exact condition (outside that window) that selects it. No inference required.

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