session_status

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

Annotations already cover read-only/non-destructive/non-open-world, so the description's real contribution is the guarantee that failure states are returned as data rather than raised as errors — meaningful behavioral context that changes how an agent sequences calls. It does not elaborate on latency or partial-failure nuance, keeping it just short of a 5.

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?

Front-loaded with the core question (is KiCad running / is the API reachable), followed by the returned detail list and one clarifying sentence. The middle enumeration is dense but every item is distinct and useful; nothing is filler.

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?

No output schema exists, yet the description enumerates the returned fields, effectively substituting for one and making the tool fully actionable. For a zero-parameter diagnostic with clear annotations, nothing an agent needs is missing.

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?

Zero parameters and 100% schema coverage, so the baseline applies; there are no parameter semantics to explain. The description instead spends its budget on return content, which is the right trade-off.

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 ('Report') and enumerates exactly what is reported: running state, IPC reachability, KiCad/API versions, instance, project directory, open documents with dirty state, and supported tools. This makes it unmistakable against siblings like board_summary or get_selection, which return schematic/board content rather than session diagnostics.

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?

'Always answers' plus the note that 'not running' and 'API disabled' come back as data tells the agent this is a safe, cheap preflight/probe call that will not error out. There is no explicit when-not or named alternative, but the intended usage context (check before acting) is clear.

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