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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is clear; the description adds real value by enumerating the diagnostic keys (storage, paapi, tagConfigured, catalogCount) an agent can inspect. It doesn't mention auth requirements, latency, or whether failures return errors vs partial 'ok' flags, which is the main remaining gap for a health endpoint.

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?

Three short sentences: purpose and return shape front-loaded, then the routing hint, then a reference pointer. No filler and nothing buried.

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?

With no parameters, no output schema, and only read-only annotations, the description carries the full burden by listing the returned fields and their meaning — including nested marketplace fields (domain, label, tagConfigured). An agent needs nothing else to call this correctly and interpret the result.

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 tool takes zero parameters, so the schema imposes no semantic burden and there is nothing for the description to disambiguate. Baseline 4 applies.

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 concrete verb+resource ('Health check') plus the exact return payload (ok, storage, paapi, trackingTag, defaultDomain, catalogCount, marketplaces[]), so an agent knows precisely what diagnostic surface it gets. The 'Use first to discover storefronts' clause cleanly separates it from siblings like get_catalog and list_marketplaces.

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?

Explicitly says 'Use first to discover storefronts', which tells the agent when to call this before other tools. It doesn't state why an agent would pick this over list_marketplaces for enumerating marketplaces, so the alternative routing is only partially covered.

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