nodriver-mcp-server

by andresolbach

Overview Schema Source Related Servers Discussions Admin

Python

Local

Check or uncheck a box

set_checked

Tick or untick a checkbox, or select a radio button, then verify the action succeeded.

Instructions

Tick or untick a checkbox, or select a radio button, and verify it took.

Use this instead of fill for anything with a checked state. fill types over a field's text, which a checkbox does not have — and its read-back compares value, which a checkbox never changes, so a fill could report success while nothing was selected.

Idempotent: asking for the state it is already in is reported and does not click. Otherwise it delivers a real CDP click, on the element or, when the input is visually hidden behind a styled label (the usual custom-control pattern), on the label that controls it. The state is read back afterwards, so a failure is an error rather than a success you cannot trust.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`uid`	Yes	Element uid from the most recent take_snapshot, e.g. "4_12". uids are invalidated whenever the page changes — if you get "unknown uid", take a fresh snapshot and retry with the new uid.
`browser`	No	Which browser to act on. Each name is an independent Chrome, created on first use. Omit for the shared default; parallel agents each need their own name.	default
`checked`	No	True to tick the box or select the radio, False to untick it. Radio buttons cannot be unticked by the browser — select a different one in the group instead.
`include_snapshot`	No	Append a fresh page snapshot to the response. Worth it when this action changes the page and take_snapshot would be your next call anyway — it saves a round trip, at the cost of a much larger response.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Addedv2.5.0Sep 25, 2026

TDQS

A4.1/5.0

Behavior1/5

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

The annotations declare idempotentHint=false, but the description explicitly says 'Idempotent: asking for the state it is already in is reported and does not click.' This is a direct contradiction, so the score is 1 per the rubric. Otherwise the description is rich, disclosing CDP clicks, hidden-label handling, read-back verification, and error behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core action, then gives the when-to-use guidance, then details behavior. Every sentence earns its place; there is no filler or repetition of schema fields.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with 4 parameters, an output schema, and a large sibling list, the description is complete: it states when to use it, why not to use fill, what happens on idempotent calls, how hidden labels are handled, how state is verified, and the radio-button limitation. The only flaw is the annotation contradiction, which is already captured under behavioral transparency.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds meaningful semantics beyond the schema, particularly around the checked parameter: requesting the current state is a no-op that is reported, while a real change triggers an actual CDP click and read-back verification.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific action and resource: 'Tick or untick a checkbox, or select a radio button, and verify it took.' It also differentiates itself from fill by explaining what fill does and does not do for checked controls.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit direction: 'Use this instead of fill for anything with a checked state,' and explains why fill is unsuitable: it types over text and compares value, which checkboxes do not have. It also warns that radio buttons cannot be unticked and directs the user to select another radio instead.

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

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