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

Goes well beyond the annotations: it discloses the acceptance rule (every schematic part by reference, every pad on its netlist net, footprint swaps allowed and recorded), the failure mode (refused with the list of differences and nothing changes), the backup artifact (circuit.before-upload.kicad_pcb), and the downstream side effects (KiCad DRC gates Gerber release, session chat gets a note).

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 core action, then constraints, then the exclusion. Each sentence carries unique information (validation rule, refusal behavior, backup filename, DRC gating, sibling exclusion) with no 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?

For a mutation tool with no output schema, the description supplies the effective outcome: what is verified, what happens on failure, what file is preserved, and what the DRC does afterward. An agent has everything needed to predict the result of a call.

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 design_id, board_base64 and note are already documented, and the description largely restates that board_base64 is the file in base64. It adds validation semantics for the board (must carry the design's circuit) rather than new parameter syntax, so the baseline 3 is correct.

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+resource+scope: 'Replace the design's board with a .kicad_pcb you routed or edited yourself.' It immediately distinguishes this full-board replacement from sibling board-editing tools and names import_kicad_project as the thing it is not.

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?

Explicit when-to-use (a board you routed or edited yourself, relating to the design's circuit) and explicit when-not-to-use ('Not for a board workspace (import_kicad_project): its board tools edit the board in place'). No inference required to route between this and its closest alternative.

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