Send Relay Message

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

Annotations already show readOnlyHint=false, idempotentHint=true, and destructiveHint=false, but the description adds meaningful behavioral nuance: it may create a Chat as a side effect, and it warns that the idempotency key must be reused only for the same logical send. This goes beyond the annotations and helps an agent avoid incorrect key reuse.

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?

Two succinct sentences with no filler. The primary action is front-loaded, and the critical idempotency caution is placed second. Every sentence adds value.

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?

The description covers the core behavior, the Chat-resolution side effect, and the idempotency caveat—enough for an agent to invoke the tool with appropriate caution. It does not describe the return value or failure behavior, but with no output schema and straightforward parameters, this is a minor gap rather than a critical one.

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 clarifies recipients as Relay Handles and gives an important idempotency-key reuse rule. However, it does not elaborate on recipient formatting, text constraints, or idempotency key semantics beyond the reuse warning, leaving the schema to carry most parameter-level detail.

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 states a specific action—resolve or create a Chat and send a text Message—and clearly identifies the target as Relay Handles. This distinguishes it from sibling relay_send_message_to_chat, which presumably targets an existing chat by ID. The verb and resource are concrete and unambiguous.

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 phrase 'to Relay Handles' gives clear context for when this tool should be used: when recipients are handles rather than chat IDs. It does not explicitly name relay_send_message_to_chat as the alternative, nor state exclusion conditions, but the handle-based targeting is a sufficiently clear usage signal.

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