AI PC Builder

Connect to the Newegg PC Builder MCP service to retrieve PC build configurations, component compatibility checks, and build recommendations. Use this skill w...

Newegg PC Builder MCP Skill

Connects Claude to the Newegg PC Builder MCP service. This skill is fully dynamic: it discovers available tools at runtime and lets the LLM decide which tool to call and how to fill its parameters. No tool names or parameter names are hard-coded, so the skill continues to work even after the MCP server updates its API.

MCP Endpoint: https://apis.newegg.com/ex-mcp/endpoint/pcbuilder Script: scripts/mcp_client.py

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Core Workflow (always follow this order)

Step 1 — Discover tools

Always start by listing available tools. Never assume tool names or parameters from previous runs or documentation.

python scripts/mcp_client.py list_tools

The output contains, for each tool:

• name — identifier to use when calling
• description — what it does (may be empty; infer from name + schema)
• inputSchema.properties — available parameters with types and descriptions
• inputSchema.required — mandatory parameters

Step 2 — Select tool and map parameters

Read the list_tools output and decide:

1. Which tool best matches the user's intent?

   • Match on description first; fall back to inferring from name + param names
   • If multiple tools apply, prefer the most specific one
   • If still ambiguous, pick the first one and note the assumption

2. How does user intent map to parameters?

   • Only use parameters present in inputSchema.properties
   • Free-text params (e.g. question, query, text): pass the user's request as a natural-language string describing their need
   • Typed/enum params: map user intent to the closest valid value
   • Leave optional params unset unless you have a clear value
   • Never invent parameters not present in the schema

Step 3 — Call the tool

python scripts/mcp_client.py call <tool_name> '<json_arguments>'

Tool name and arguments are determined at runtime from Step 2. Example:

python scripts/mcp_client.py call v2allin '{"question": "gaming PC RTX 5090 9800X3D best price"}'

Windows PowerShell (important)
PowerShell parses outer double quotes before Python runs. Using \"...\" inside "..." often breaks the JSON string (you may see errors like Got: {\ or “invalid JSON”). Prefer one of:

1. Single-quote the whole JSON (no backslash escapes needed):

   python scripts/mcp_client.py call v2allin '{"question": "gaming PC RTX 3070"}'
   

2. JSON in a file (most reliable for long or nested payloads):

   Set-Content -Path args.json -Encoding utf8 '{"question": "gaming PC RTX 3070"}'
   python scripts/mcp_client.py call v2allin @args.json
   

3. Stdin (pipe or redirect):

   '{"question": "gaming PC RTX 3070"}' | python scripts/mcp_client.py call v2allin -
   

The script supports @path\to\file.json and - for stdin so shells never need to escape inner double quotes.

Where to change things

• Skill + script (recommended): keep examples and mcp_client.py in sync — document PowerShell rules here, and use @file / - in the client to avoid quoting bugs.
• Repo-only docs do not fix agents that load this skill from ~/.agents; updating the skill is the right place for portable behavior.

Step 4 — Interpret the response

Parse the JSON output. Common response shapes:

{ "result": { "summary": "...", "popular": [...], "valued": [...] } }

• summary non-null → use as the primary answer text
• popular / valued arrays present → list the builds
• All result fields null → service returned no data; tell the user and offer to answer from general knowledge instead
• isError: true → report the error and suggest retry

Step 5 — Present results

• Build list: name, total price, key components, brief description
• Compatibility check: clear yes/no with reasoning
• Component details: specs, price, compatibility notes
• No results from API: explain clearly, then offer a manual recommendation

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Edge case handling

Situation	Action
list_tools returns 0 tools	Report service unavailable; answer from training knowledge
Tool description is empty	Infer purpose from name + parameter names
Schema has no required	Treat all params as optional; pass what you have
All response fields null	No data for this query; say so and fall back to general knowledge
HTTP error on list_tools	Report error; do not proceed to call step
HTTP error on call	Retry once; if still failing, fall back to general knowledge
Multiple tools match	Pick most specific; briefly note the choice

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Script reference

scripts/mcp_client.py uses Python standard library only (3.6+, no pip needed). Handles both application/json and text/event-stream responses automatically.

python scripts/mcp_client.py list_tools
    → prints all tools with full parameter schemas

python scripts/mcp_client.py call <tool_name> '<json_args>'
    → calls the tool and prints the JSON response

python scripts/mcp_client.py call <tool_name> @args.json
    → reads JSON arguments from a UTF-8 file (good on Windows)

echo '<json>' | python scripts/mcp_client.py call <tool_name> -
    → reads JSON from stdin

Errors go to stderr with a non-zero exit code. Invalid JSON prints a short hint for PowerShell users.