browser_get_cookiesRead cookies from the open browser, optionally filtered by URL or name, to inspect or debug site sessions.
Read cookies from the browser, optionally filtered by URL and/or name.
| Name | Required | Description | Default |
|---|---|---|---|
| url | No | Only return cookies that would be sent to this URL | |
| name | No | Only return cookies with this name |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden, and it only implies that an active browser session is required ('from the browser'). It says nothing about which browsing context/tab cookies come from, what happens with no active session, or whether httpOnly/secure cookies are included. The read-only nature is inherently low-risk, which keeps this from dropping further.
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?
A single 12-word sentence that front-loads the action and resource and appends the filter qualifier. Nothing is wasted and nothing important is buried.
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 and no annotations, the description should say more about the returned shape (names, values, domains, expiry) and the required browser-session precondition. For a simple two-param read tool it is adequate, but an agent still lacks the return-value picture.
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 baseline is 3; the description's 'optionally filtered by URL and/or name' merely restates the two documented properties. It adds no matching semantics beyond the schema, such as how URL matching interacts with cookie domain/path scoping.
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 ('Read cookies from the browser') plus the two optional filter dimensions, which is enough for an agent to distinguish it from browser_set_cookie. It does not explicitly name or contrast against any sibling, so it stops 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?
There is no when-to-use or when-not-to-use guidance and no routing to the obvious alternative (browser_set_cookie for writing, browser_evaluate for JS-level access). The optional-filter mention describes parameters, not tool selection, so usage must be inferred from the name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.