Write a belief artifact to the CogOps Knowledge Vault. Beliefs are durable system understanding — what Entroly thinks the codebase is. Each belief carries machine-auditable frontmatter: claim_id, entity, status, confidence, sources, last_checked. Args: entity: The system entity this belief is abo...
AI agents use vault_write_belief to create or update resources in Entroly Context Engine — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Entroly Context Engine environment.
This tool creates and stores structured data (belief artifacts) in a knowledge system. It is Write-category because it modifies persistent state by adding new belief records to a vault, and these modifications are reversible (beliefs can presumably be updated or deleted). It is not Destructive because no irreversible deletion occurs.
From the tool's definition vault_write_belief writes a belief artifact to the CogOps Knowledge Vault. The description explicitly states it 'Write[s] a belief artifact' and indicates it creates durable records with metadata fields (claim_id, entity, status, confidence, sources,…
Documented attack patterns abuse exactly the kind of access vault_write_belief gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Entroly Context Engine, and nothing reaches the server without passing your rules. This is the rule we recommend for vault_write_belief:
{
"version": "1",
"default": "deny",
"tools": {
"vault_write_belief": {
"limits": [
{
"counter": "vault_write_belief_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}vault_write_belief stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Write a belief artifact to the CogOps Knowledge Vault. Beliefs are durable system understanding — what Entroly thinks the codebase is. Each belief carries machine-auditable frontmatter: claim_id, entity, status, confidence, sources, last_checked. Args: entity: The system entity this belief is about (e.g., 'auth::token_rotation') title: Human-readable title body: The belief content (markdown) confidence: Machine-assigned confidence 0.0-1.0 (default: 0.7) status: observed|inferred|verified|stale|hypothesis (default: inferred) sources: Comma-separated source paths (e.g., 'src/auth.rs:142,src/token.rs:58') derived_from: Comma-separated component names that produced this belief. It is categorised as a Write tool in the Entroly Context Engine MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Entroly Context Engine MCP server in PolicyLayer and add a rule for vault_write_belief: 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 Entroly Context Engine. Nothing to install.
vault_write_belief 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 vault_write_belief 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 vault_write_belief. 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.
vault_write_belief is provided by the Entroly Context Engine MCP server (juyterman1000/entroly). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Entroly Context Engine, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
52 Entroly Context Engine tools catalogued and risk-classified — across an index of 43,000+ MCP servers.