mcp-vdd

Generate Spec

vdd_specify

Destructive

Generate a tactical action item spec with user stories, acceptance criteria, MoSCoW priorities, and impact checks. Overwrites the spec file; pass an actionItemId or description.

Instructions

VDD Phase 4: Generate vdd/specs//spec.md for one tactical action item — user stories, Always/Ask/Never boundaries, Given/When/Then acceptance criteria (AC), MoSCoW priorities, non-functional requirements, and impact verification. Overwrites the spec file. Pass actionItemId (e.g. "A-001") or a freeform description to skip the V/S/T chain. Use for a NEW spec; to resolve leftover [NEEDS CLARIFICATION] markers in an existing spec use vdd_clarify instead.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`feature`	No	Feature name (spec directory name)
`description`	No	Freeform description input
`projectRoot`	No	Project root: directory that constitution.md and the vdd/ folder are written to and resolved against (default ".")	.
`actionItemId`	No	Tactical action item ID (e.g., "A-001")

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 declare destructiveHint=true, but the description goes further by naming exactly what is overwritten ('Overwrites the spec file'). It also discloses the skip-chain behavior, adding useful behavioral context beyond the annotation.

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?

Three sentences contain only necessary information, front-loaded with the phase and output artifact. The overwrite warning and sibling routing are compact and placed after the core purpose, with no filler or repetition.

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 destructive, complex workflow tool with many sibling phases, the description addresses the core decision (new spec vs clarification), the two input paths, and the file that will be affected. The presence of an output schema reduces the need to describe return values, and the description leaves no critical gap for correct invocation.

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 coverage is 100%, so the baseline is 3. The description adds value by clarifying the relationship between actionItemId and description, giving a concrete ID format example ('A-001'), and explaining that either can bypass the V/S/T chain. This exceeds the schema alone.

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?

Description states a specific verb (Generate), a concrete resource (vdd/specs/<id>/spec.md), and the scope of the action item generation. It explicitly contrasts itself with vdd_clarify, so an agent can distinguish it from siblings without inspecting schemas.

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 description gives explicit when-to-use guidance ('Use for a NEW spec') and when-not-to-use guidance with a named alternative ('to resolve leftover [NEEDS CLARIFICATION] markers in an existing spec use vdd_clarify instead'). It also explains the input modes: pass actionItemId or freeform description to skip the V/S/T chain.

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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