diagnose

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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint=false, but the description goes beyond them: it states 'makes NO paid model call and NEVER perturbs state' and details exactly which checks are performed ('CLI presence and --version, whether an API key is set, and the breaker's read-only snapshot'). This adds genuine behavioral context about side effects and cost, exceeding what the annotations alone provide.

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 three sentences: purpose and when-to-use, output summary, and safety constraints. It is front-loaded with 'Read-only health check', uses imperative 'REACH FOR THIS', and every clause serves a purpose. No filler, and the structure guides the agent from 'what' to 'when' to 'what it costs'.

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 no-parameter, no-output-schema tool, the description fully covers behavior, side effects, and expected report contents (reachability, model, timeout, breaker gate, fix line, and rollup status). An agent knows exactly what it will get and what it costs, making it complete enough for correct invocation decisions.

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 is empty with 0 parameters, so the baseline per the rubric is 4. The description appropriately focuses on tool behavior rather than parameter details, since there are no parameters to document. It adds no parameter semantics because there are none to describe.

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 opens with 'Read-only health check of every reasoning backend', a specific verb/resource pairing that clearly defines scope. It then lists concrete trigger conditions ('when a council came back degraded, an oracle is unexpectedly missing') which sharply distinguishes it from sibling ask_* and configure_* tools, and enumerates exactly what it reports (reachability, resolved model, timeout, circuit-breaker gate, fix line). This leaves no ambiguity about the tool's 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 tells the agent when to reach for it: 'REACH FOR THIS when a council came back degraded...' and adds the wise precaution 'before relying on it'. It also clarifies the safety profile ('Cheap and safe to call speculatively') which informs usage frequency. While it doesn't name sibling tools by name, the explicit when-conditions are sufficient to route an agent correctly.

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