P&ID: Instrument Index

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

Annotations give readOnlyHint=true, and the description adds meaningful context beyond that: it states the drawing is not modified, that rows derive from `pid_graph` (not manual input), and that `csv_path` is the only file written. The last point usefully reconciles the read-only hint with an optional file write, which annotations alone would leave ambiguous.

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?

Two tightly written sentences; the output/scope is front-loaded and the provenance and write-target facts follow. No filler, and the output schema covers the return shape.

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 an output schema present the description needn't explain return values, and annotations cover the safety profile. The description supplies source, side effects, and scope of writes, leaving only parameter-level detail (scope/tolerance) to the schema. Adequate and near-complete.

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 100%, so the baseline is 3. The description only elaborates on `csv_path` (the sole written file) and says nothing about `scope` or `tolerance`. It adds marginal meaning over the schema without compensating for anything, so baseline 3 fits.

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 output (every instrument bubble with ISA-5.1 reading and connections), which is a clear verb+resource for an index-extraction tool. It references the source sibling (`pid_graph`) rather than restating the title. It doesn't explicitly contrast with the nearest siblings like pid_equipment_list or pid_tag_parse, so sibling differentiation is only implied.

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 (generate an instrument index for a P&ID) but there is no explicit when-to-use or when-to-choose-this-over-alternatives guidance. The `pid_graph` provenance statement clarifies the data source but is not a selection rule. An agent must infer that this is the index tool versus pid_equipment_list.

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