mcp-vdd

Validate Impact

vdd_validate

Destructive

Validate the full VDD chain after implementation: traceability matrix, drift/orphan detection, uncovered goals, impact metrics, and 28 assumption checks. Overwrites vdd/impact-report.md.

Instructions

VDD Phase 8: Validate the full chain — bidirectional traceability matrix, drift detection, orphan detection, uncovered vision goals, impact metrics vs targets, and 28 S&T assumption checks across 7 gates. Writes (overwriting) vdd/impact-report.md. Run after implementation is complete; for a lightweight per-feature consistency check use vdd_analyze, and for the matrix alone use vdd_trace. artifactFiles maps artifact path→content for serverless runs where the tool cannot read the filesystem — omit it when running locally against projectRoot.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`feature`	No	Feature name (spec directory name)
`projectRoot`	No	Project root: directory that constitution.md and the vdd/ folder are written to and resolved against (default ".")	.
`artifactFiles`	No	Map of artifact path → content for serverless validate/drift detection

Output Schema

TableJSON Schema

Name	Required	Description
`_sdt`	Yes	Strategy-and-Tactic instructions for the next step
`error`	No	Error message when the phase fails
`_phase`	Yes	VDD phase that produced this result
`output`	No	Additional structured phase output
`success`	Yes	Whether the phase completed successfully
`artifact`	No	Primary artifact produced or returned
`gateResult`	No	Quality-gate result, when the phase runs a gate

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.1.3Sep 24, 2026

changedInput schema / properties / projectRoot / description

Previous value: -"Path to project root directory"New value: +"Project root: directory that constitution.md and the vdd/ folder are written to and resolved against (default \".\")"

Changed1 schema field changedv0.1.2Sep 24, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": false,
+  "properties": {
+    "_phase": {
+      "description": "VDD phase that produced this result",
+      "type": "string"
+    },
+    "_sdt": {
+      "description": "Strategy-and-Tactic instructions for the next step",
+      "type": "string"
+    },
+    "artifact": {
+      "description": "Primary artifact produced or returned",
+      "type": "string"
+    },
+    "error": {
+      "description": "Error message when the phase fails",
+      "type": "string"
+    },
+    "gateResult": {
+      "additionalProperties": false,
+      "description": "Quality-gate result, when the phase runs a gate",
+      "properties": {
+        "checks": {
+          "description": "Number of checks run",
+          "type": "number"
+        },
+        "passed": {
+          "description": "Whether the quality gate passed",
+          "type": "boolean"
+        },
+        "total": {
+          "description": "Total number of checks",
+          "type": "number"
+        }
+      },
+      "required": [
+        "passed",
+        "checks",
+        "total"
+      ],
+      "type": "object"
+    },
+    "output": {
+      "additionalProperties": {},
+      "description": "Additional structured phase output",
+      "propertyNames": {
+        "type": "string"
+      },
+      "type": "object"
+    },
+    "success": {
+      "description": "Whether the phase completed successfully",
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "success",
+    "_phase",
+    "_sdt"
+  ],
+  "type": "object"
+}

First observedv0.1.0Sep 24, 2026

TDQS

A4.9/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, but the description goes further by disclosing the exact side effect: it writes and overwrites vdd/impact-report.md. It also transparently explains the artifactFiles parameter's serverless purpose and when to omit it locally. This exceeds what the annotation alone provides and is consistent with it.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is dense but every clause earns its place: scope, side effect, timing, alternatives, and parameter behavior are all covered without redundancy. The main action and output file are front-loaded, with usage routing following naturally.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a complex multi-faceted validation tool, the description covers what is validated, the output artifact and its overwrite behavior, when to run it, which siblings to use instead for narrower needs, and the special artifactFiles mode. With an output schema present and all parameters documented, nothing essential for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds genuine extra meaning for artifactFiles by explaining it is for serverless runs where the filesystem is unreadable and should be omitted for local runs against projectRoot. This goes beyond the schema's path→content map definition, though feature and projectRoot remain at schema-level detail.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names the specific verb 'Validate' and the resource 'the full chain', then enumerates precisely what that includes: traceability matrix, drift detection, orphan detection, uncovered vision goals, impact metrics, and assumption checks. It also distinguishes itself from siblings by explicitly naming vdd_analyze and vdd_trace as different-scope tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The instruction 'Run after implementation is complete' states the when-to-use condition, and the description gives explicit alternatives: vdd_analyze for lightweight per-feature checks and vdd_trace for the matrix alone. This is unambiguous routing guidance that an agent can act on directly.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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