validate_assumption

SERVERMeridian SOURCE@meridianmcp/mcp

Medium RISK CLASS

Category Write

Parameters 63 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-ajc3xc-meridian/validate-assumption.md

WHAT IT DOES

What validate_assumption does on Meridian

AI agents use validate_assumption to create or update resources in Meridian, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Meridian environment.

Parameter	Type	Required	Description
`symbol`	string	—	Optional symbol within file_path.
`finding`	string	Yes	What you found that confirms or refutes the assumption.
`confirmed`	boolean	Yes	true = assumption holds; false = invalidated (fires a blocking HITL).
`file_path`	string	—	Optional file path the finding is anchored to (code-anchored note).
`session_id`	string	—	Session firing the validation; linked to the blocking HITL on invalidation.
`decision_id`	string	Yes

Parameters from the server's own tool schema.

RISK

Why validate_assumption is rated Medium

The tool writes persistent state (assumption_status stamp, code-anchored note) and can trigger a blocking HITL event that halts downstream work. While it has significant side effects on workflow coordination, it does not delete/overwrite irreversibly nor execute code — it modifies decision metadata and conditionally fires a blocking human-in-the-loop queue entry.

From the tool's definition Stamps the decision's assumption_status (confirmed|invalidated), saves a code-anchored note with your finding, and when confirmed=false fires a BLOCKING HITL so work depending on the decision pauses for human judgment

Risk signalsAccepts file system path (file_path)

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs validate_assumption safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Meridian, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For validate_assumption, this is the rule to start with:

validate_assumption Rate-limited

validate_assumption 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "validate_assumption": {
      "limits": [
        {
          "counter": "validate_assumption_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Meridian, apply this rule, and every validate_assumption call is checked against it from then on.

FAQ

Questions about validate_assumption

What does the validate_assumption tool do? +

[SUPPORT] Confirm or invalidate the assumption a pinned decision rests on, in one call — no phase switching. Stamps the decision's assumption_status (confirmed|invalidated), saves a code-anchored note with your finding, and when confirmed=false fires a BLOCKING HITL so work depending on the decision pauses for human judgment. Use the moment you discover whether an assumption holds (a planning-session prospect moment). Persistent-state disclosure: on hosted Meridian, supplied text and project/session metadata are sent to and stored in Meridian's service; self-hosted deployments keep them in the configured local SQLite/Postgres database. This data is visible in the dashboard/API and later project context or handoffs. Delete individual tasks, notes, or decisions where supported, or delete the project/account using the documented controls. Do not include secrets. It is categorised as a Write tool in the Meridian MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does validate_assumption accept? +

validate_assumption accepts 6 parameters: symbol, finding, confirmed, file_path, session_id, decision_id. Required: finding, confirmed, decision_id. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on validate_assumption? +

Register the Meridian MCP server in PolicyLayer and add a rule for validate_assumption: 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 Meridian. Nothing to install.

What risk level is validate_assumption? +

validate_assumption is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit validate_assumption? +

Yes. Add a rate_limit block to the validate_assumption 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.

How do I block validate_assumption completely? +

Set action: deny in the PolicyLayer policy for validate_assumption. 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.

What MCP server provides validate_assumption? +

validate_assumption is provided by the Meridian MCP server (@meridianmcp/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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Govern customer-ops agents →Argument validation →Scoped token →