pcb_create_room

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

With no annotations, the description carries the full burden and does reasonably well: it discloses the mutation ('Creates a confinement constraint rule'), the target context ('active PCB'), the geometry semantics (rectangular region from two corners), and the default behavior for empty components ('applies to all'). It omits error conditions (name collision, room overlapping existing rooms, what happens to already-placed components) and permission/precondition requirements.

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 action, then a compact structure (summary, args, returns) that scans well. Slightly padded: the 'Returns' block is redundant with the existing output schema, and the example lists in Args add length without new information.

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 6-param mutation tool with 0% schema coverage and no annotations, the description supplies units, defaults, and examples – enough to call it correctly. The main gap is sibling disambiguation against pcb_create_design_rule and failure modes; the Returns block is unnecessary since an output schema exists.

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 description coverage is 0%, so the description must compensate and it does: units are given for x1/y1/x2/y2 (mils), name examples are provided, and components is documented as comma-separated designators with an explicit empty-string default meaning. This is meaningfully more than the schema's bare titles.

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+resource: 'Create a room for component grouping on the active PCB', and clarifies the underlying object ('confinement constraint rule' defining a rectangular region). It does not distinguish itself from sibling pcb_create_design_rule, which is the closest functional overlap, 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 implied rather than stated: the description explains that components are assigned via scope expression and shows example names/designators, which hints at the workflow. But there is no explicit when-to-use vs. pcb_create_design_rule, no prerequisites (does an active PCB must be open and un-routed?), and no exclusions.

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