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fitter_inspect_url

Fetch a URL and return candidate selectors/paths so you can build a correct fitter config first try. Detects client-rendered SPAs and warns when render:true is needed. Read-only; pair with fitter_run.

Instructions

Fetch a URL and return a compact structure outline plus candidate selectors/paths, so you can author a fitter config that matches on the first try instead of guessing selectors and getting nulls. For JSON it lists gjson paths with types and sample values; for HTML it lists repeated elements (candidate array_config root_path / list rows) and link/heading selectors. For client-rendered SPAs (content built by JavaScript), a plain fetch sees only an empty shell — the output warns when it detects one; pass render:true to render it in a headless browser first (mirrors what a browser_config scrape would see). Read-only helper that does NOT extract data — use it before fitter_run, then fitter_run to actually extract.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
urlYesHTTP(S) URL to fetch and inspect for its structure and candidate selectors.
renderNoRender the page in a headless browser (Playwright/Chromium) before inspecting — needed for client-rendered SPAs whose content is built by JavaScript and is absent from the raw HTML. Requires browser support (the fitter-mcp:playwright image or a local Playwright install).
response_typeNoOptional hint for how to read the response: json, HTML, xpath or XML. Empty auto-detects from the Content-Type/body.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. Addedv1.8.2

TDQS

A5/5.0
Behavior5/5

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

No annotations are provided, so the description carries the full burden. It clearly states the tool is read-only and does not extract data, and explains behavior for different content types (JSON, HTML, SPAs) and the render option.

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 detailed but each sentence adds unique value, covering purpose, output, parameter usage, and distinctions from execution tools. It is front-loaded with the primary purpose.

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?

Despite no output schema, the description describes the output as a 'compact structure outline plus candidate selectors/paths' and gives specifics for JSON and HTML. It also covers the render behavior for SPAs, making the tool's behavior well understood.

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

Parameters5/5

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

The description expands on each parameter beyond the schema: url as the target, render for SPAs, and response_type as an optional hint with auto-detection. It explains why the parameters matter and how they affect the output.

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?

States a specific verb ('Fetch a URL and return a compact structure outline') and differentiates from sibling tools by positioning it as an inspection step before fitter_run. Clearly identifies the tool's role.

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?

Explicitly states when to use it ('before fitter_run') and what it does not do ('does NOT extract data'), plus provides guidance on when to set render:true for SPAs. Also mentions the response_type hint.

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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