Fetches the current CLOB order book for a specific Polymarket outcome token, returning top bid and ask levels with sizes, mid-price, spread in both decimal and basis points, and total bid/ask depth in USD. Use this to assess execution quality and market-making opportunities before placing an orde...
Part of the Syenite server.
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AI agents use prediction.book to create or modify resources in Syenite. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call prediction.book repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Syenite.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"prediction.book": {
"limits": [
{
"counter": "prediction.book_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Syenite policy for all 46 tools.
These attack patterns abuse exactly the kind of access prediction.book gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Fetches the current CLOB order book for a specific Polymarket outcome token, returning top bid and ask levels with sizes, mid-price, spread in both decimal and basis points, and total bid/ask depth in USD. Use this to assess execution quality and market-making opportunities before placing an order — wide spreads indicate higher edge for makers; shallow depth signals potential slippage on larger size. Requires tokenId, which is obtained from the clobTokenIds field in prediction.trending or prediction.search results. Does not place or modify orders.. It is categorised as a Write tool in the Syenite MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Syenite MCP server in PolicyLayer and add a rule for prediction.book: 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 Syenite. Nothing to install.
prediction.book 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 prediction.book 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 prediction.book. 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.
prediction.book is provided by the Syenite MCP server (@syenite/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 46 Syenite tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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