ellmos-filecommander-mcp

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Preview File

fc_preview_file

Read-onlyIdempotent

Inspect a local file's MIME type, size, and previewability first. Retrieve bounded inline content only when explicitly requested via include_content.

Instructions

Liefert zuerst MIME-Typ, Größe und Vorschaufähigkeit einer lokalen Datei. Inhalt wird nur nach include_content=true und nur bis zum festen Inline-Limit als MCP-Text-, Bild- oder Resource-Content zurückgegeben.

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": {
      "path": "<path>"
    },
    "name": "fc_preview_file"
  }
}

Input Schema

Name	Required	Description	Default
`path`	Yes	Existing local file to inspect or preview
`include_content`	No	Explicitly request bounded inline content after inspecting metadata

Output Schema

Name	Required	Description	Default
`uri`	Yes
`path`	Yes
`reason`	Yes
`mime_type`	Yes
`size_bytes`	Yes
`preview_kind`	Yes
`content_request`	Yes
`content_included`	Yes
`max_inline_bytes`	Yes
`content_requested`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Addedv1.11.5Nov 2, 2026

TDQS

A3.8/5.0

Behavior4/5

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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the bar is lower; the description still adds real behavior: metadata is returned first regardless, content is gated on include_content=true, content is truncated at a fixed inline limit, and the returned content kinds (text, image, resource) are named. The limit is not quantified, which is the main remaining gap.

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, no filler, and the most important fact (metadata returned first, content conditional) is front-loaded. Nothing could be removed without losing information.

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

Completeness4/5

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

With an output schema present, the description needn't enumerate return fields, and annotations carry the safety profile; what remains essential — the opt-in content gate and the inline cap — is covered. Only the actual size of the inline limit and the read_file/fc_file_info distinction are missing.

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 both parameters are already documented and 'path' needs nothing more. The description reinforces include_content's consequence (bounded inline content, specific content types) but largely restates what the schema property text already says; baseline 3 applies.

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?

States a specific verb and resource: it inspects a local file and returns MIME type, size and preview capability, then optionally bounded content. The two-phase 'metadata first, content on request' behavior is distinctive. However, it never names how this differs from siblings like fc_file_info or fc_read_file, which plausibly return metadata / full content.

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

Usage Guidelines3/5

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

The phrase 'zuerst ... Vorschaufähigkeit' implies this is a pre-flight inspection step before fetching content, and 'nur nach include_content=true' implies the gating. But there is no explicit when-to-use/when-not guidance and no pointer to the alternative tool for full reads.

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