add_via

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

With no annotations provided, the description carries the burden of disclosing behavior. It reveals that all distances are in millimetres regardless of document units, dry_run=true prevents writing, and expected_sha256 must be provided for the actual write. This is useful behavioral context, but it does not explain what 'verified' entails or potential failure scenarios, so not a 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?

The description is three sentences, front-loaded with the core purpose, then units, then the safe workflow. Every sentence adds distinct value with no redundancy or filler.

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?

The output schema exists, so return values are covered. The description covers the core workflow and units, but leaves gaps: the meaning of 'verified', the role of path/txid/layer_before/layer_after, and any prerequisites beyond having an existing segment. For a complex PCB editing tool, this is moderately complete but not comprehensive.

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%, and the description only elaborates on dry_run and expected_sha256. The other eight parameters (x, y, trace_id, via_style, path, txid, layer_before, layer_after) receive no semantic explanation beyond their names/types. This is insufficient for a 10-parameter tool, especially with obscure fields like layer_after and expected_sha256.

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 a specific action ('Add a verified ViaStyle trace point') on a specific resource ('existing segment'), clearly differentiating it from sibling tools like add_trace or set_via_style. The verb and object are unambiguous.

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 provides clear workflow context: distances are always in millimetres, and the dry_run preview step precedes the actual write, with the requirement to pass expected_sha256 after inspection. However, it does not explicitly mention when to choose this tool over alternatives (e.g., add_trace, move_via), so it misses the 'when-not' guidance for a 5.

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