list_active_instances

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

readOnlyHint=true is already declared, and the description is consistent with it. It adds one genuinely useful behavioral fact beyond the annotations: only processes with an active PyNet IPC pipe are returned. It omits any note on cost, blocking, or whether the scan is exhaustive across all supported hosts.

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?

A single front-loaded sentence with no filler; the app list in parentheses is dense but informative rather than wasteful. Nothing would be lost by trimming, but nothing is padded either.

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 zero parameters, an output schema present, and readOnlyHint covering safety, the description says enough to invoke the tool correctly: it tells the agent what qualifies as a result. A brief note on ordering or scope (all hosts vs. current document) is the only missing piece.

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 nothing for the description to disambiguate and the baseline of 4 applies. No parameter content is needed or missing.

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?

Specific verb and resource: 'Scans the system for running host processes ... with an active PyNet IPC pipe', and it enumerates the host apps (Autodesk, Rhino, PyNET for Tekla/Presto). It does not name any sibling to distinguish itself from, so it falls short of a 5.

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?

Usage is only implied: an agent can infer that this is a discovery step before send_command or viewer tools, but the description never says when to use it or which alternative (e.g. check_plugin_status) to prefer. The 'active IPC pipe' qualifier hints at the selection criterion but does not spell it out.

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