Read all elements matching a CSS selector from a connected browser session and return their content or attributes. Use it to extract repeated page data in bulk without copying credentials.
Read all matching elements
| Name | Required | Description | Default |
|---|---|---|---|
| tab | No | ||
| attr | No | ||
| what | No | ||
| profile | No | Browser ID from sleeper_sessions; optional with one connected browser. | |
| selector | Yes |
Changes observed during successful MCP inspections.
v2.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full burden, yet it adds nothing beyond "read." It is silent on return format, whether attr/what alter the output, whether profile is required, and any limits on the number of matched elements returned.
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?
It is a single front-loaded phrase with no wasted words, but it is terse to the point of under-specification rather than genuinely concise. Brevity here costs clarity instead of buying it.
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 5-parameter tool with no annotations, no output schema, and 20% schema coverage, the description is far too thin. An agent would not know what a call returns or how attr/what/selector interact.
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 only 20% (just profile is documented), leaving tab, attr, what, and selector unexplained. The description's phrase "matching elements" loosely gestures at selector but adds no meaning for the other three parameters.
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 ("read") and resource ("matching elements") with a plural scope, so the basic intent is inferable. However, it does not distinguish itself from close siblings like sleeper_read, sleeper_get, sleeper_find, or sleeper_extract, leaving the agent to guess how it differs.
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?
There is no indication of when to use this tool versus sleeper_read (singular) or sleeper_extract. The word "all" hints at multi-element retrieval, but no when-to-use or exclusion guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.