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

Annotations already declare destructiveHint=true, openWorldHint=true, and idempotentHint=false, so safety framing is partly covered. The description adds one genuinely new behavioral fact — that ordinary channel communication is unaffected — but it never explains what enabling A2A actually changes, whether it can be undone, or what the destructive aspect entails. The 'unaffected' reassurance also sits in mild tension with a destructive annotation.

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?

A single front-loaded sentence with no filler; the scope qualifier is placed after the action, which reads naturally. It is efficient, though the terseness leaves the burden unmet for a destructive mutation tool.

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, open-world state mutation with no output schema and an undocumented required parameter, the description omits what A2A mode does, what state changes on enable, and how to revert. The single sentence is not sufficient for an agent to invoke this safely or correctly.

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 50%: the 'connection' credential is well documented in the schema, but the required 'enabled' boolean has no description and the tool description adds nothing about it. With this coverage gap the description should compensate by explaining what opting in/out means, and it does not.

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 has a clear verb ('Opt this agent into') and a resource ('A2A'), so the intent is parseable, but 'A2A' is unexplained jargon and the description does nothing to separate this tool from siblings like a2a_tasks or a2a_task_update. An agent can guess the purpose but not confidently situate it among the other A2A tools.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives, despite seven other a2a_* siblings. The clause about ordinary channel communication is a scope note, not usage guidance. The agent gets no signal about when enabling A2A is appropriate.

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