open_schematic

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

Annotations cover the safety profile (destructiveHint=false, openWorldHint=false), but the description adds genuinely useful context beyond them: it returns a local URL, that URL lives on the MCP server's machine (a real gotcha for a remote caller), and it requires the schematic extra. It never explains why readOnlyHint is false even though the operation looks like a pure view, leaving a small gap.

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?

Three tight sentences with the core action front-loaded and no filler. Minor structural looseness in the trailing sentence, which packs two unrelated details ('loaded design' and '#id instances') together, keeps it from a 5.

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 does its job by stating what is returned (a local URL) and the requirement to have the schematic extra and a loaded design. The agent has enough to call it correctly; the only missing piece is guidance on how the returned URL should be consumed or when this tool is the right choice.

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 the path parameter's meaning ('Instance path to focus; omit for the top') is already fully documented. The description's phrase 'supports anonymous #id instances' adds a hint about accepted id forms but does not define syntax or format, so the schema carries the load and 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?

The description gives a specific verb and resource: 'Serve an interactive browser schematic of the current design.' That is far more informative than a restated name and the nature of the tool is unmistakable. It does not, however, explicitly differentiate itself from schematic-adjacent siblings such as annotate_schematic or get_schematic_selection, so it falls short of a 5.

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?

Usage is only implied: 'requires the schematic extra' and 'Uses the loaded design' hint at prerequisites, and the mention of the current design implies a design must already be loaded. There is no explicit when-to-use, when-not-to-use, or routing to an alternative tool, which is the core of this dimension.

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