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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), and the description adds real value beyond them: it discloses that layers are derived from the solved stackup, that standards default to IPC-2221 + IPC-6012 Class 2, that it reuses the POST /api/compliance/check engine, and that results are labelled 'caller-asserted' when user_request is omitted. It does not discuss cost, rate limits, or failure modes, so a 4 rather than 5.

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 action and scope, then defaults and invocation guidance. Dense but every clause carries information; the standards acronym list is slightly list-heavy but justified for an audit tool.

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 no output schema, the description compensates by describing the return shape (per-rule pass/fail with severities and remediation). Combined with default/derivation rules and the caller-asserted labelling behavior, an agent has enough to invoke it correctly; only minor gaps like expected runtime or result-size remain.

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%, so the baseline is 3. The description goes beyond the schema by explaining that layers and stackup_config are derived when omitted and by restating the default standard set, which is the key behavioral detail an agent needs when calling with no arguments. It does not expand on the region-name form of standards beyond what the schema already documents.

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 ('Audit') and resource ('the solved stackup against PCB standards'), enumerates the standards families, and names the concrete deliverable (per-rule pass/fail with severities and remediation). This clearly distinguishes it from siblings like run_stackup_solver or run_pdn_analysis without needing to open any 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?

Gives an explicit usage condition: 'call with no arguments once a stackup exists,' which tells the agent both the precondition (a solved stackup must exist) and the default invocation. It does not name a specific alternative tool to use instead, so it falls just short of full routing guidance.

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