watch
Manage watch expressions for monitoring variable values during debugging.\n\nActions:\n- add: Add a watch expression (requires expression)\n- remove: Remove by watchId\n- list: List all watches\n- evaluate_all: Evaluate all enabled watches (optional callFrameId)\n- clear_all: Clear all watches
This record as markdown: /tools/io-github-vmoranv-jshookmcp/watch.md
What watch does on Jshookmcp
AI agents invoke watch to trigger actions in Jshookmcp. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why watch is rated High
Evaluating watch expressions executes code in a debug context, with potential side effects.
From the tool's definition Evaluate all enabled watches, monitor variable values during debugging
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
The rule that runs watch safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Jshookmcp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For watch, this is the rule to start with:
watch stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Jshookmcp, apply this rule, and every watch call is checked against it from then on.
Questions about watch
Manage watch expressions for monitoring variable values during debugging.\n\nActions:\n- add: Add a watch expression (requires expression)\n- remove: Remove by watchId\n- list: List all watches\n- evaluate_all: Evaluate all enabled watches (optional callFrameId)\n- clear_all: Clear all watches. It is categorised as a Execute tool in the Jshookmcp MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Jshook MCP server in PolicyLayer and add a rule for watch: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Jshookmcp. Nothing to install.
watch is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the watch rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for watch. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
watch is provided by the Jshook MCP server (@jshookmcp/jshook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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