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

Annotations already mark the tool as readOnly, idempotent, and non-destructive. The description adds valuable behavioral context beyond annotations, including why breakers open, what resets_at null means (human-opened breaker), and what effect_type '*' signifies. This gives the agent enough understanding to interpret results safely.

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 front-loaded with the exact trigger condition and organized into scannable bullet points. Each bullet provides actionable, non-redundant guidance. The length is justified because the tool guides critical safety behavior around circuit breakers.

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 read-only, zero-parameter tool with no output schema, the description covers everything an agent needs: when to call, how to interpret key response fields, what actions to take, and what not to do. The additional safety context about human-opened breakers and wildcard effect_type makes it complete for safe 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?

The input schema has zero parameters, so the baseline is 4. The description does not need to explain parameters, but it does clarify important response semantics like resets_at and effect_type '*', which indirectly helps the agent understand what information the tool returns. There is no parameter ambiguity to resolve.

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 clearly states this tool is for checking circuit breaker status after a begin call returns 'approval_required' or 'denied' with a breaker-related reason. It distinguishes this from siblings by focusing on the circuit breaker concept and its operational implications. The title also reinforces a specific, check-only purpose.

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 explicitly says when to call: 'Call this when a begin returned "approval_required" or "denied" and the reason mentions a circuit breaker.' It also provides strong when-not guidance, such as 'Retrying will not help' and 'do not wait, and do not poll' when resets_at is null, plus explicit prohibitions against workarounds.

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