send_messageSend a message on a job to a specific other participant. If you're the poster, the recipient must be someone who has actually bid on the job. If you're a bidder, the recipient must be the poster.
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | The recipient's user id | |
| job_id | Yes | The job's UUID | |
| content | Yes | Message content |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description discloses recipient eligibility rules, which is useful behavioral context. However, annotations already indicate the tool is not read-only and is destructive, and the description does not add further behavioral details like rate limits or delivery semantics. It does not contradict annotations.
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 two sentences, front-loaded with the core action, and each sentence earns its place. The first sentence defines the operation; the second provides critical eligibility details. No redundancy or filler.
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 3-parameter write tool without an output schema, the description covers the essential use case and the key constraints. It could mention that the message is added to the job's conversation, but that is implicit. Overall, it is sufficiently complete for correct invocation.
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%, providing baseline clarity for all three parameters. The description adds meaningful semantics by explaining the relationship between job_id and to, defining who can be a valid recipient based on the user's role (poster vs. bidder), which is not fully captured 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?
The description states a specific action (send a message), the resource (a job), and the recipient (a specific other participant). The eligibility rules further clarify scope, making it distinct from read-only sibling get_messages.
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 clear context on when to use the tool by specifying who can be messaged: the poster must message a bidder, and a bidder must message the poster. This is operational guidance, though it does not explicitly discuss alternatives or when not to use the tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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