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

With no annotations the description carries the full burden, and it does disclose a meaningful behavioral trait beyond the schema: the concurrency guard that the call is refused if the task already advanced. It also clarifies the lifecycle semantics of the state enum and that text/artifacts are optional except for input-required. It omits error-shape and permission details.

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, densely packed sentence that front-loads the action and the state options, with the refusal guard placed last where it belongs. It is efficient, though the many clauses make it slightly harder to scan than a fully structured definition.

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 mutation tool with no annotations and no output schema, the definition covers what an agent needs: the action, the states, and the refusal guard. Auth and parameter formats are handled by the 100%-covered schema, so the remaining gaps (return shape, error specifics) are minor.

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%, so the parameters are already well documented. The description adds only modest meaning — that input-required means 'say what you need' and that text/artifacts ride alongside the state — which is close to a restatement of the schema's enum list. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Answer an A2A task addressed to you') and enumerates the exact state transitions it performs, so an agent immediately knows what the tool does. It never names a sibling (e.g. a2a_inbox) to disambiguate reading vs. responding, so it falls short of a 5.

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?

Gives a clear use context (answering a task addressed to you) and a concrete when-not condition: 'Refused if the task already moved on.' It does not name alternative tools or describe prerequisites like the auth/scope requirement, so it stops short of explicit alternatives.

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