Search for compounds by CAS Registry Number
AI agents call search_by_cas_number to retrieve information from PubChem MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries PubChem's chemical database to retrieve compound information using a CAS number as the search parameter. It performs data lookup without creating, modifying, deleting, or executing any operations. The scope is restricted to reading publicly available chemical data, making it a Read-category tool with low risk and high confidence.
From the tool's definition Tool name is 'search_by_cas_number' and description states 'Search for compounds by CAS Registry Number' — the verb 'search' and absence of modification or deletion language indicates a retrieval operation with no side effects.
Attacks that exploit this kind of access
Search for compounds by CAS Registry Number. It is categorised as a Read tool in the PubChem MCP Server MCP Server, which means it retrieves data without modifying state.
Register the PubChem MCP Server MCP server in PolicyLayer and add a rule for search_by_cas_number: 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 PubChem MCP Server. Nothing to install.
search_by_cas_number 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 search_by_cas_number 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 search_by_cas_number. 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.
search_by_cas_number is provided by the PubChem MCP Server MCP server (k-lordbodin7/pubchem-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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