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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered; the description adds the genuinely non-obvious fact that the output is a link handed to the user rather than a server-side action. It does not mention link lifetime, auth requirements, or what the link looks like, which keeps it at 4.

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?

One sentence, front-loaded with the return value, with no redundant restatement of the title or annotations. Every clause (editor modes, by-hand intent) carries information.

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 one required parameter, full schema coverage, and no output schema, the description's job is to explain the return value and intent — it does both explicitly ("returns the link... for the user to view or edit by hand"). Nothing needed to call it correctly is 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 single parameter design_id is already documented. The description adds no format, ID-source, or constraint detail beyond the schema, so the baseline 3 applies.

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?

Names a specific verb (returns) and a specific artifact (the link that opens a design in PCBEditor), plus clarifies the editor modes (2D, 3D, schematic). Crucially it makes clear this produces a URL rather than performing the edit, distinguishing it from siblings like edit_board.

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?

"for the user to view or edit by hand" gives a clear selection cue: use this when a human, not the agent, should interact with the design. It does not explicitly name alternatives such as edit_board or get_board for programmatic cases, so it stops short of a 5.

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