Send Flow Message

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

Beyond the annotations (destructiveHint=true, idempotentHint=false), it discloses the critical non-obvious behavior that the platform accepts a message even when nothing is waiting for it, so a success-looking call may have done nothing. It gives the verification remedy and the constraint that the message must match what the step expects.

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?

Front-loaded with the action and effect, then constraints, then the failure mode and remedy. Three sentences, all load-bearing, no restatement of the title or schema.

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 destructive, non-idempotent write with no output schema, the description covers prerequisites, silent-no-op risk, and post-call verification, which is what an agent needs to call it safely. It does not describe what the call itself returns, leaving the agent dependent on the follow-up status check, but that is a minor gap given the guidance provided.

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%, so a 3 is the baseline; the description adds genuine semantics on top by stating that the message value must be exactly the one the Wait For Message step waits for, which is a correctness rule not encoded in the schema.

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?

It names a specific verb and resource (send a message to a paused flow execution) and states the effect (resumes the flow, which continues to the next step). It also cites the underlying API (sn_fd.FlowAPI.sendMessage), which pins down exactly what operation this is versus siblings like execute_flow, test_flow, or cancel_flow.

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?

It states a real precondition (the execution must be paused in a Wait For Message step) and an explicit guard ('Only when the user asked'), plus a follow-up action (check get_flow_context_status). It stops short of naming sibling alternatives such as execute_flow for starting a flow, but the when-to-use condition is unambiguous.

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