Replace old_str with new_str in the named memory file. Fails (no partial write) when old_str is absent or matches more than once. Writes a new content-addressed file_cid and signs the receipt. Mirrors the str_replace verb in Anthropic's context-management-2025-06-27 memory tool spec. When to use:...
Risk signalsAccepts file system path (path)
Part of the emem — Earth memory protocol server.
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AI agents use memory_str_replace to create or modify resources in emem — Earth memory protocol. 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 memory_str_replace 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 emem — Earth memory protocol.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"memory_str_replace": {
"limits": [
{
"counter": "memory_str_replace_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full emem — Earth memory protocol policy for all 81 tools.
These attack patterns abuse exactly the kind of access memory_str_replace 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.
Replace old_str with new_str in the named memory file. Fails (no partial write) when old_str is absent or matches more than once. Writes a new content-addressed file_cid and signs the receipt. Mirrors the str_replace verb in Anthropic's context-management-2025-06-27 memory tool spec. When to use: Call when the LLM issues a str_replace against its memory file — typical for small targeted edits. The strict single-match contract is the contract Claude expects: an LLM that sees a single-match diff knows the change applied where it intended.. It is categorised as a Write tool in the emem — Earth memory protocol MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the emem — Earth memory protocol MCP server in PolicyLayer and add a rule for memory_str_replace: 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 emem — Earth memory protocol. Nothing to install.
memory_str_replace 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 memory_str_replace 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 memory_str_replace. 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.
memory_str_replace is provided by the emem — Earth memory protocol MCP server (oci:ghcr.io/vortx-ai/emem:latest). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 81 emem — Earth memory protocol tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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