package_exists
Boolean registry existence check. USE WHEN: about to emit a package name in an install command but unsure it exists; verifying a name generated from training data. RETURNS: {exists}.
This record as markdown: /tools/dev-depscope-mcp/package-exists.md
What package_exists does on Depscope
AI agents call package_exists to retrieve information from Depscope without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
package | string | Yes | |
ecosystem | string | Yes |
Parameters from the server's own tool schema.
Why package_exists is rated Low
This tool only queries a package registry to verify whether a package name exists, returning a simple boolean. It performs no writes, executes nothing, and has no side effects. Misuse potential is minimal — at worst an agent gets a false/misleading existence result.
From the tool's definition Boolean registry existence check... RETURNS: {exists}
Attacks that exploit this kind of access
The rule that runs package_exists safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Depscope, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For package_exists, this is the rule to start with:
package_exists is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Depscope, apply this rule, and every package_exists call is checked against it from then on.
Questions about package_exists
Boolean registry existence check. USE WHEN: about to emit a package name in an install command but unsure it exists; verifying a name generated from training data. RETURNS: {exists}. It is categorised as a Read tool in the Depscope MCP Server, which means it retrieves data without modifying state.
package_exists accepts 2 parameters: package, ecosystem. Required: package, ecosystem. The full parameter table on this page comes from the server's own tool schema.
Register the Depscope MCP server in PolicyLayer and add a rule for package_exists: 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 Depscope. Nothing to install.
package_exists is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the package_exists 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 package_exists. 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.
package_exists is provided by the Depscope MCP server (cuttalo/depscope-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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