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

Annotations already declare read-only, idempotent, open-world, non-destructive, so the safety profile is covered. The description adds genuine behavior: omitting versionId follows "Latest", the returned result already carries name/owner/visibility/version, and the containing drawing is auto-selected when focusing. It stops short of describing rendering failure modes or what the viewer result looks like beyond the field list.

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 organized by use case (history, compare, board view, focus). Dense but every sentence adds a distinct rule; no filler or restated name.

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 10-param tool with a nested object and an output schema, the description covers the main decision branches and the non-obvious defaults. Gaps remain around the tab/view duplication, subspecies of focus fields (change, layers), and error/access conditions, so not fully complete.

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?

With 0% schema description coverage and 10 params including a nested focus object, the description carries real weight: it explains the versionId omission rule, that compareBase/compareHead must be passed together, what documentKind/documentId select, and the focus shape ({ view, refs | nets | areaMm }) plus sheet override precedence and KiCad path format. It leaves tab vs. view duality, change, and layers unexplained.

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 and resource ("Open the embedded BoardRepo viewer, version history or comparison") plus scope ("accessible board"), and explicitly separates itself from ordinary read tools. An agent can tell immediately that this opens an interface rather than returning data.

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 explicit when-to-use branches: version history via versionId, Compare via the paired compare*VersionId params, Board view via documentKind/documentId, and focus after read_schematic/query_design. It also states a clear exclusion ("Ordinary read tools do not open this interface") and tells the agent get_board is unnecessary first.

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