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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the agent knows this is a non-destructive write. The description adds useful context that the message is for human-in-the-loop communication, but it does not disclose delivery behavior, persistence, recipient routing, or authentication requirements. With annotations covering the safety profile, this is adequate but not rich.

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 sentences, front-loaded with the core action, followed by concise usage context. Every phrase earns its place with no filler or redundancy.

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 simple send-message tool with full schema coverage and annotations that cover safety, the description is nearly complete. It explains purpose and usage contexts. The main missing element is explicit routing against sibling pcc_chat_history, but that is a minor gap 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%, and the schema documents all three parameters including the role enum and its default. The description adds no additional parameter-level semantics beyond identifying the recipient as an operator or agent. Baseline 3 is appropriate when the schema already carries the parameter meaning.

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 verb and resource: 'Send a chat message to a kernel's operator or agent.' It clearly conveys the action and target. However, it does not distinguish this tool from sibling pcc_chat_history, which likely handles the read side of the same conversation domain.

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 gives explicit usage contexts: human-in-the-loop communication during job execution, troubleshooting, and escalation. This is clear guidance on when to use it. It stops short of naming alternatives or stating when not to use it, such as reading existing chat history instead.

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