Guild Wars 1 Build Compiler

Validate a build against GW1 rules

validate_build

Read-onlyIdempotent

Check a build (professions, attributes, 8 skills by exact English name) against Guild Wars 1 rules: one elite max, profession/attribute ownership, primary attributes, duplicates, rank ranges. Returns { valid, errors, warnings } without encoding — use encode_template instead when you also want the template code, since it runs these same rules and refuses on any error.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "primary": "<primary>",
      "attributes": "<attributes>",
      "skills": "<skills>"
    },
    "name": "validate_build"
  }
}

Input Schema

Name	Required	Description
`forPvp`	No	Set true for a PvP character's bar (PvP versions of split skills are only valid then).
`skills`	Yes	Exactly 8 skill names in bar order. Use null for an empty slot. Names must be exact English skill names.
`forHero`	No	Set true if this bar is for a hero (PvE-only skills are flagged)
`primary`	Yes	Primary profession, e.g. "Dervish"
`secondary`	No	Secondary profession, e.g. "Monk". Omit or "None" for none.
`attributes`	Yes	Attribute point allocations (template format caps this at 15 entries)
`unlockedSkillIds`	No	Optional: unlocked skill ids from a GWToolbox account export (/exportaccount). Skills outside this list are flagged as warnings.

Output Schema

Name	Required	Description
`valid`	Yes	Whether the build is legal in-game
`errors`	Yes	Blocking problems; empty when valid
`warnings`	Yes	Non-blocking advisories

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedAug 11, 2026
- addedInput schema / additionalProperties
```
Added value: +false
```
Changed1 schema field changedJul 29, 2026
- addedInput schema / properties / forHero / description
```
Added value: +"Set true if this bar is for a hero (PvE-only skills are flagged)"
```

Changed1 schema field changedJul 24, 2026

addedInput schema / properties / forPvp

Added value: +{
+  "default": false,
+  "description": "Set true for a PvP character's bar (PvP versions of split skills are only valid then).",
+  "type": "boolean"
+}

Changed4 schema fields changedJul 21, 2026

changedInput schema / properties / attributes / description

Previous value: -"Attribute point allocations"New value: +"Attribute point allocations (template format caps this at 15 entries)"

addedInput schema / properties / attributes / maxItems
```
Added value: +15
```

addedOutput schema / properties / errors / items / properties / suggestions

Added value: +{
+  "description": "Closest-match names, on resolution errors",
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

addedOutput schema / properties / warnings / items / properties / suggestions

Added value: +{
+  "description": "Closest-match names, on resolution errors",
+  "items": {
+    "type": "string"
+  },
+  "type": "array"
+}

Changed5 schema fields changedJul 21, 2026
- addedInput schema / properties / attributes / items / properties / attribute / maxLength
```
Added value: +64
```
- addedInput schema / properties / primary / maxLength
```
Added value: +64
```
- addedInput schema / properties / secondary / maxLength
```
Added value: +64
```
- changedInput schema / properties / skills / items / anyOf
```
Previous value: -[
-  {
-    "type": "string"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "maxLength": 64,
+    "type": "string"
+  },
+  {
+    "type": "null"
+  }
+]
```
- addedInput schema / properties / unlockedSkillIds / maxItems
```
Added value: +8192
```

Changed5 schema fields changedJul 20, 2026

removedOutput schema / properties / code

Removed value: -{
-  "description": "Official in-game template code (successful encode only)",
-  "type": "string"
-}

addedOutput schema / properties / errors / description

Added value: +"Blocking problems; empty when valid"

addedOutput schema / properties / valid / description

Added value: +"Whether the build is legal in-game"

addedOutput schema / properties / warnings / description
```
Added value: +"Non-blocking advisories"
```

addedOutput schema / required

Added value: +[
+  "valid",
+  "errors",
+  "warnings"
+]

First observedJul 12, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare readOnly and idempotent, and the description adds useful behavioral context: it returns {valid, errors, warnings} and does not encode. It also implies a non-refusing behavior versus encode_template. No contradiction with annotations.

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?

Two sentences, front-loaded with the core function, and no wasted words. The second sentence concisely provides the return shape and directs to an alternative tool.

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?

The description covers the validation rules, return structure, and the relationship to a sibling tool. With rich schema and output schema present, nothing critical is missing for an agent to decide and invoke correctly.

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

Parameters3/5

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

Schema description coverage is 100%, so the schema already explains each parameter thoroughly (e.g., exact English names, null for empty slot, rank 0-12). The description adds no new parameter detail beyond naming build components, so baseline 3 applies.

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 opens with a specific verb 'Check' and identifies the exact resource (build against GW1 rules), listing the validation categories. It explicitly distinguishes from the sibling encode_template, making the tool's purpose unmistakable.

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 ('without encoding') and when-not-to-use guidance by directing to encode_template for template-code needs, noting that encode_template runs the same rules and refuses on errors. This is clear and actionable.

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

All Guild Wars 1 Build Compiler tools Inspect

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