prefix_function
Compute the KMP prefix/failure function array, with optional pattern occurrence counting.
This record as markdown: /tools/io-github-malamutemayhem-unclick-mcp-server/prefix-function.md
What prefix_function does on UnClick
AI agents invoke prefix_function to trigger actions in UnClick. 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.
| Parameter | Type | Required | Description |
|---|---|---|---|
text | string | Yes | Input string (max 1,000,000 chars) |
pattern | string | — | Optional pattern to count occurrences of |
Parameters from the server's own tool schema.
Why prefix_function is rated High
This tool performs a computational algorithm (KMP string matching/prefix function) on provided input. It executes a computation rather than reading stored data, writing/modifying data, or performing destructive/financial actions. The blast radius is low since it only processes input data algorithmically with no side effects on external systems.
From the tool's definition 'Compute the KMP prefix/failure function array, with optional pattern occurrence counting'
Attacks that exploit this kind of access
The rule that runs prefix_function safely
PolicyLayer is an MCP gateway: it sits between your AI agents and UnClick, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For prefix_function, this is the rule to start with:
prefix_function 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 UnClick, apply this rule, and every prefix_function call is checked against it from then on.
Questions about prefix_function
Compute the KMP prefix/failure function array, with optional pattern occurrence counting. It is categorised as a Execute tool in the UnClick MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
prefix_function accepts 2 parameters: text, pattern. Required: text. The full parameter table on this page comes from the server's own tool schema.
Register the UnClick MCP server in PolicyLayer and add a rule for prefix_function: 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 UnClick. Nothing to install.
prefix_function 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 prefix_function 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 prefix_function. 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.
prefix_function is provided by the UnClick MCP server (@unclick/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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