health_check

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

With no annotations, the description carries the full behavioral burden and does so well: it discloses that no account is required, that behavior changes depending on SPHIOR_API_KEY (local mode + usable tool list vs. adding a security summary), and that it touches no server state. Notably absent is any statement about latency or whether it performs network I/O in the keyed case, which matters for a connectivity diagnostic.

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 first, then the two operating modes, then the use case. Every sentence contributes a distinct fact and nothing is repeated from structured fields.

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 zero-parameter diagnostic with no annotations and no output schema, the description covers both return shapes (mode/reachability/tool list, optionally security summary) and the credential precondition. An agent has everything needed to call it 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 there is no parameter semantics for the description to compensate for; baseline 4 applies. The schema is an empty object and nothing in the description is required to clarify inputs.

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 — "Report the server's mode and reachability" — which an agent can act on immediately. It is distinguishable from siblings like get_security_summary, though it doesn't explicitly say when to prefer that tool for a fuller security view.

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?

"Use this to debug connection issues" gives a clear triggering condition, and the API-key/no-key split tells the agent what to expect in each environment. It stops short of naming alternatives or exclusions, but the usage context is unambiguous.

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