Inspect element

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds useful behavior beyond that by naming the failure mode ("Fails with element_not_found for unknown IDs") and describing the depth of the response payload. It stops short of saying how large the payload can get or whether the ID must come from the current session, but the added error semantics are a real contribution.

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 a compact return-value list, then the usage rule — no filler sentences. The long field enumeration is dense but each item is informative; a bulleted or clause-broken structure would read slightly better than the single packed paragraph.

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?

There is no output schema, so the description carries the full burden of describing the return value and it does so field by field, plus the error case and sibling routing. For a single-parameter read tool, nothing an agent needs in order 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 there is only one parameter, so the baseline is already satisfied; the description nonetheless adds provenance meaning by specifying the ID comes "from get_canvas_skeleton or a create result", which the schema's bare "Element ID." does not convey.

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 ("Inspect one element by ID") and then enumerates exactly what is returned: non-default settings, controlsHint, bounding box, computed-style excerpt, text, overflow flag, parent chain and children. This is clearly distinguishable from get_canvas_skeleton (whole canvas), get_widget_controls (key catalogue) and update_settings (mutation).

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 guidance ("Use it before update_settings to see the current values and their exact shapes") plus a routing rule for the sibling ("call get_widget_controls when you need a key that is not in controlsHint"). It also states where the required ID comes from, which pre-empts the most likely misuse.

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