P&ID: Insert Symbol

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

With only readOnlyHint=false as annotation, the description carries the full burden and delivers rich behavioral detail: it defines the block on first use (`defined`), creates a missing family layer (`layers_created`), writes an ACADMCP_PID payload for readers without the catalogue, returns ports in WCS, and reports invalid ISA-5.1 tags via `tag_warnings` with `drawing_critique` flagging. These side effects and error-handling behaviors are exactly what an agent needs to invoke the tool safely.

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 purpose is front-loaded in the first sentence, followed by structured behavioral details with backticked output keys. It is slightly dense with parenthetical key names, but every sentence contributes needed context and nothing is wasted.

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?

Given 16 parameters with full schema descriptions and an existing output schema, the description is nearly complete: it covers key side effects, output ports, and error handling, and points to the connecting tool. It lacks explicit when-to-use guidance versus siblings, but otherwise an agent has enough to invoke correctly.

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 adds a small amount of meaning beyond the schema—mentioning ISA-5.1 tag validation and the ACADMCP_PID payload—but does not provide per-parameter semantics that the schema does not already cover better.

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 first sentence states a specific verb ('Insert'), resource ('catalogue symbol as a real block'), and key attributes ('TAG attributes and named ports'), clearly distinguishing it from generic block insertion tools via the P&ID catalogue context. An agent can identify this as the P&ID symbol insertion tool without opening the schema.

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 implies usage for P&ID catalogue symbols and mentions a follow-up step ('connect them with pid_line_draw'), but it does not explicitly say when to choose this over alternatives like block_insert or pid_symbol_list. There is clear context but no exclusions or named alternatives for the insertion decision itself.

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