P&ID: Symbol Catalogue

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

With `readOnlyHint: true` already declaring the safety profile, the description adds meaningful behavioural context: source standards, figure naming, millimetre sizing at A3/A1 scale, and how `scale` at insertion affects size. It does not discuss pagination or return shape, but that is partly covered by the output schema.

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?

The description is front-loaded with purpose, then adds source and sizing details in clearly ordered sentences. Every sentence contributes useful context, though the formatting with line breaks is slightly loose for a short 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 catalogue tool with one optional filter and an existing output schema, the description supplies enough context: what it contains, where symbols come from, and how sizes are expressed. Nothing critical for correct invocation appears to be 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%, and the description adds no input-parameter meaning beyond what the schema already provides for `family`. The baseline of 3 is appropriate when the schema carries parameter semantics fully.

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?

The description states that this tool returns the symbol catalogue that `pid_symbol_insert` can place, including ports and variant options. It distinguishes itself from the insertion sibling by being the catalogue source rather than the action tool, so an agent can immediately understand its role.

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?

The description names `pid_symbol_insert`, implying this tool is used to discover symbols before insertion, but it does not explicitly say when to use this tool versus alternatives or when not to use it. Usage is therefore implied rather than spelled out.

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