reuse-before-generate

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check_before_building

Search GitHub, npm, and other registries for existing codebases and SaaS competitors before building from scratch. Avoid rebuilding what already exists.

Instructions

Run before building from scratch. Searches GitHub, GitLab, npm, crates.io, NuGet, Hugging Face, Docker Hub, Maven Central, RubyGems, and Packagist across multiple query angles to find existing codebases, and provides targeted web search queries for finding commercial SaaS competitors.

Input Schema

TableJSON Schema

Name	Required	Description
`query`	No	Search query or project description
`queries`	No	RECOMMENDED: 2-4 distinct technical search queries / keywords maintainers would use (e.g. ['gnome speech to text', 'gnome whisper dictation', 'linux offline voice typing']).
`keywords`	No	Optional search keywords
`description`	No	Description of what you want to build

Schema Changelog

Changes observed during successful MCP inspections.

Changed18 schema fields changedv0.2.5Sep 23, 2026

removedInput schema / $schema

Removed value: -"http://json-schema.org/draft-07/schema#"

removedInput schema / additionalProperties
```
Removed value: -false
```

changedInput schema / properties / description / description

Previous value: -"Plain-language description of the project/module about to be built — what it does, not how. The more specific, the better the match quality."New value: +"Description of what you want to build"

removedInput schema / properties / description / minLength
```
Removed value: -10
```

changedInput schema / properties / keywords / description

Previous value: -"REQUIRED: 3-4 precise search terms YOU infer from the description, using your own understanding of what the user actually means — do this especially when the description is vague, informal, or from a non-native speaker. Pick the concrete domain noun a maintainer would actually put in their README, not a generic category word: e.g. for 'thing that checks my code doesn't have secret keys by mistake' prefer [\"git\", \"secrets\", \"detect\", \"leak\"] over [\"secret\", \"scanner\", \"detect\", \"git\"] — 'scanner' is broad enough to pull in unrelated security-tool listicles, while 'leak'/'secrets' matches how gitleaks/trufflehog actually describe themselves. Avoid generic tooling-ecosystem words (mcp, agent, server, tool, app) unless the description has nothing more specific — they return noise (awesome-lists, unrelated MCP servers) rather than real competitors. Critically, favor the word a maintainer would use to describe WHAT THE TOOL IS over the word describing the USER'S PROBLEM: a real 'pretty JSON in the terminal' tool likely calls itself a 'viewer' or 'processor', not a 'pretty-printer'/'colorizer'; a real static-site link checker likely says it validates 'rendered HTML', not 'static site alt-text'. If your first guess doesn't match, mentally simulate the README of the tool you're picturing and pull words straight from that sentence."New value: +"Optional search keywords"

removedInput schema / properties / keywords / items
```
Removed value: -{
-  "type": "string"
-}
```
removedInput schema / properties / keywords / maxItems
```
Removed value: -6
```
removedInput schema / properties / keywords / minItems
```
Removed value: -3
```

addedInput schema / properties / keywords / oneOf

Added value: +[
+  {
+    "items": {
+      "type": "string"
+    },
+    "type": "array"
+  },
+  {
+    "type": "string"
+  }
+]

removedInput schema / properties / keywords / type
```
Removed value: -"array"
```
removedInput schema / properties / queries / additionalProperties
```
Removed value: -false
```

changedInput schema / properties / queries / description

Previous value: -"Optional high-quality intent inferred semantically by the calling agent: category names what this is, outcome says what it accomplishes, synonyms supplies distinct terminology maintainers or product makers may use, constraints supplies up to 8 must-have properties, priorities supplies up to 4 ordered preferences, and artifactType says whether the desired result is an application, hosted service, CLI, or library. Older callers may omit these optional fields; the server will infer conservative fallbacks."New value: +"RECOMMENDED: 2-4 distinct technical search queries / keywords maintainers would use (e.g. ['gnome speech to text', 'gnome whisper dictation', 'linux offline voice typing'])."

addedInput schema / properties / queries / items
```
Added value: +{
+  "type": "string"
+}
```

removedInput schema / properties / queries / properties

Removed value: -{
-  "artifactType": {
-    "enum": [
-      "application",
-      "service",
-      "cli",
-      "library"
-    ],
-    "type": "string"
-  },
-  "category": {
-    "minLength": 2,
-    "type": "string"
-  },
-  "constraints": {
-    "items": {
-      "minLength": 2,
-      "type": "string"
-    },
-    "maxItems": 8,
-    "type": "array"
-  },
-  "outcome": {
-    "minLength": 2,
-    "type": "string"
-  },
-  "priorities": {
-    "description": "Ordered preferences from most important to least important, such as [\"Android\", \"iOS\"]. Both can appear in results, but earlier entries receive more ranking weight.",
-    "items": {
-      "minLength": 2,
-      "type": "string"
-    },
-    "maxItems": 4,
-    "type": "array"
-  },
-  "synonyms": {
-    "minLength": 2,
-    "type": "string"
-  }
-}

removedInput schema / properties / queries / required

Removed value: -[
-  "category",
-  "outcome",
-  "synonyms"
-]

changedInput schema / properties / queries / type
```
Previous value: -"object"New value: +"array"
```

addedInput schema / properties / query

Added value: +{
+  "description": "Search query or project description",
+  "type": "string"
+}

removedInput schema / required

Removed value: -[
-  "description",
-  "keywords"
-]

Changed1 schema field changedv0.2.4Jul 25, 2026

addedInput schema / properties / queries

Added value: +{
+  "additionalProperties": false,
+  "description": "Optional high-quality intent inferred semantically by the calling agent: category names what this is, outcome says what it accomplishes, synonyms supplies distinct terminology maintainers or product makers may use, constraints supplies up to 8 must-have properties, priorities supplies up to 4 ordered preferences, and artifactType says whether the desired result is an application, hosted service, CLI, or library. Older callers may omit these optional fields; the server will infer conservative fallbacks.",
+  "properties": {
+    "artifactType": {
+      "enum": [
+        "application",
+        "service",
+        "cli",
+        "library"
+      ],
+      "type": "string"
+    },
+    "category": {
+      "minLength": 2,
+      "type": "string"
+    },
+    "constraints": {
+      "items": {
+        "minLength": 2,
+        "type": "string"
+      },
+      "maxItems": 8,
+      "type": "array"
+    },
+    "outcome": {
+      "minLength": 2,
+      "type": "string"
+    },
+    "priorities": {
+      "description": "Ordered preferences from most important to least important, such as [\"Android\", \"iOS\"]. Both can appear in results, but earlier entries receive more ranking weight.",
+      "items": {
+        "minLength": 2,
+        "type": "string"
+      },
+      "maxItems": 4,
+      "type": "array"
+    },
+    "synonyms": {
+      "minLength": 2,
+      "type": "string"
+    }
+  },
+  "required": [
+    "category",
+    "outcome",
+    "synonyms"
+  ],
+  "type": "object"
+}

First observedv0.2.3Jul 22, 2026

TDQS

A3.9/5.0

Behavior4/5

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

With no annotations, the description carries the full burden of behavioral disclosure. It names the exact registries covered, notes that multiple query angles are used, and states that it also generates targeted web search queries for competitor research. It stops short of describing the return format or error/edge-case behavior, but it is substantially transparent for a read-oriented search tool.

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 one focused, front-loaded sentence with no filler: the usage trigger comes first, followed by the precise scope. The long list of registries is justified because it defines the tool's coverage and prevents confusion with sibling tools.

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

Completeness3/5

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

For a discovery tool with no output schema, the description explains what it searches and partially what it returns ('provides targeted web search queries'). However, it does not specify the format or nature of the codebase-search results, nor does it address how this tool relates to reuse_before_generate.

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 documents all four parameters. The description adds only a general hint about 'multiple query angles,' which explains how queries are used at a high level but does not add detail beyond the schema's parameter descriptions.

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

Purpose4/5

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

The description clearly states the tool's action and resource: it runs before building from scratch, searches a specific set of code registries, and finds existing codebases. It does not explicitly contrast itself with reuse_before_generate, so sibling differentiation is only implicit rather than named.

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

Usage Guidelines4/5

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

The opening phrase gives an explicit trigger condition: 'Run before building from scratch.' This tells the agent when to use the tool, but it does not provide explicit when-not-to-use guidance or name the sibling as an alternative.

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

Deploy Server

check_before_building

Instructions

Input Schema

Schema Changelog

TDQS

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