Return the biggest risers and fallers between the two latest snapshots. Compares every area's composite score in the most recent snapshot against the snapshot before it and returns the areas that improved most (improvers — score fell) and worsened most (decliners — score rose). Needs at least two...
Risk signalsBulk/mass operation — affects multiple targets
Part of the The Cracks Index server.
Free to start. No card required.
AI agents call top_movers to retrieve information from The Cracks Index without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though top_movers only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"top_movers": {}
}
}See the full The Cracks Index policy for all 15 tools.
These attack patterns abuse exactly the kind of access top_movers gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Return the biggest risers and fallers between the two latest snapshots. Compares every area's composite score in the most recent snapshot against the snapshot before it and returns the areas that improved most (improvers — score fell) and worsened most (decliners — score rose). Needs at least two snapshots; returns an explanatory empty payload otherwise. Read-only, area-level aggregates only, no personal data.. It is categorised as a Read tool in the The Cracks Index MCP Server, which means it retrieves data without modifying state.
Register the The Cracks Index MCP server in PolicyLayer and add a rule for top_movers: 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 The Cracks Index. Nothing to install.
top_movers 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 top_movers 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 top_movers. 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.
top_movers is provided by the The Cracks Index MCP server (https://api.fynqo.app/mcp/cracks/). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 15 The Cracks Index tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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