cache_set
Set a value in the optional Redis companion cache
This record as markdown: /tools/1999azzar-project-guardian-mcp-server/cache-set.md
What cache_set does on Project Guardian MCP
AI agents use cache_set to create or update resources in Project Guardian MCP, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Project Guardian MCP environment.
Why cache_set is rated Medium
cache_set performs a write operation that creates or modifies data in a Redis cache. This is reversible (values can be overwritten or deleted via cache_delete) and has limited blast radius—misuse would affect only cached data, not persistent project state or critical systems. The 'optional' nature of the Redis companion suggests it augments rather than controls core functionality.
From the tool's definition Tool description states 'Set a value in the optional Redis companion cache', which is a write operation that creates or modifies cached data.
Attacks that exploit this kind of access
The rule that runs cache_set safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Project Guardian MCP, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For cache_set, this is the rule to start with:
cache_set stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Project Guardian MCP, apply this rule, and every cache_set call is checked against it from then on.
Questions about cache_set
Set a value in the optional Redis companion cache. It is categorised as a Write tool in the Project Guardian MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Project Guardian MCP server in PolicyLayer and add a rule for cache_set: 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 Project Guardian MCP. Nothing to install.
cache_set is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the cache_set 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 cache_set. 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.
cache_set is provided by the Project Guardian MCP server (1999azzar/project-guardian-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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