Mithwire MCP

browser_storage_set

Set local or session storage key/value entries in a browser session to seed or reset state, with optional clearing first.

Instructions

Set local/session storage key/value entries.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "session_id": "<session_id>",
      "kind": "<kind>",
      "entries": "<entries>"
    },
    "name": "browser_storage_set"
  }
}

Input Schema

Name	Required	Description	Default
`kind`	Yes
`entries`	Yes
`session_id`	Yes
`clear_first`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.5.1Oct 18, 2026

TDQS

C2.7/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full disclosure burden and largely fails it. It never says whether entries are merged with or overwrite existing keys, what clear_first does to existing storage, or whether this persists across navigation — all material for a mutation tool.

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

Conciseness4/5

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

A single front-loaded sentence with no wasted words. It is efficient, though its brevity borders on under-specification rather than genuine conciseness.

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

Completeness2/5

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

An output schema exists, so return values need not be described. However, for a four-parameter mutation tool with zero annotation and zero schema-description coverage, the description omits the destructive/merge semantics and session requirements an agent needs to invoke it safely.

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

Parameters2/5

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

Schema description coverage is 0%, so the description must compensate. It only hints at 'key/value entries' and the local/session distinction, leaving clear_first — a potentially destructive flag — completely unexplained in prose, and giving no format or size guidance for the entries object.

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

Purpose4/5

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

States a specific verb ('Set') and resource ('local/session storage key/value entries'), which clearly separates it from siblings like browser_storage_get and browser_storage_clear. It does not explicitly name those siblings, so it lands at a clear-but-undifferentiated 4.

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

Usage Guidelines2/5

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

There is no when-to-use guidance, no mention of prerequisites (e.g. an active session_id), and no routing to alternatives such as browser_storage_get for reads or browser_storage_clear for wipes. The agent must infer all of this 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.

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