ssh_reachable

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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, but the description adds real value: 'read-only, in-band' and the clarification that it targets a different machine than the KVM appliance, plus the runtime-override behavior of host. It doesn't cover timeout/latency behavior, but that's minor here.

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-loads the core question, then layers scope, routing guidance, and the host override in a tight structured block. Every sentence carries information, though the host paragraph slightly restates the schema description.

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 reachability probe with full annotation coverage and no output schema, the description is nearly complete: it states the operation, the distinct target machine, and when to prefer it. It could note failure semantics (what an unreachable result implies), but nothing critical for correct invocation 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?

Schema coverage is 100%, so both parameters are already documented in the schema, establishing the baseline of 3. The description reinforces the host override with a use case (install-time DHCP address), but adds no syntax or format detail beyond the schema.

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?

Opens with a precise question ('Is the managed host's OS reachable over SSH?') that names a specific verb-like operation and resource, and explicitly disambiguates the target as the host *behind* the KVM, distinct from the appliance. This separates it cleanly from siblings like ssh_exec, ssh_discover, and healthcheck.

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?

Gives clear context ('use this to prefer remote recovery before asking a user to physically intervene'), which tells the agent when this probe is the right call. It does not explicitly name when-not or enumerate alternatives (e.g. ssh_discover/ssh_exec), so it stops short of a full routing rationale.

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