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image-resize-convert-compress-watermark

Upload an image to work on

image_upload

Send an image to this hosted endpoint. There is no filesystem here, so instead of a path you upload the file once with image_upload and then pass its name as path (or inside paths) to image_info, image_resize, image_convert, image_compress, image_crop, image_thumbnails, image_batch_resize and image_dominant_colors. PNG, JPEG, BMP, GIF and TIFF are accepted and the format is read from the file's magic bytes, not from the name. Give exactly one of image_base64 or url. url: fetch a public file instead of pasting base64 (recommended above about 10 KB): writing out a real photo as base64 is a long tool call and 50 KB or more can stall the turn before the upload is sent, while a url costs one line and the fetch happens here (10 second timeout, at most 3 redirects, public http(s) hosts only, 2 MB cap). Uploads are kept for your token between calls; image_files lists them and image_delete_upload removes one. A file this server writes is named the same way and comes back as a download link valid for one hour, served with the real image content type. The request body cap is 256 KB, which is about 190 KB of image once base64-encoded.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
urlNourl: fetch a public file instead of pasting base64 (recommended above about 10 KB). Public http(s) only; private, link-local and this endpoint's own zone are refused
nameYesName to refer to this image by: 1-64 characters of letters, digits, underscore or dash, e.g. "shot"
image_base64NoThe image file, base64-encoded

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observed

TDQS

A4.8/5.0
Behavior5/5

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

With no annotations provided, the description carries the full burden and does so thoroughly. It discloses file format handling via magic bytes, the 256 KB request cap, URL restrictions (timeout, redirects, public hosts, 2 MB cap), persistence of uploads per token, cleanup tools, and download link expiry. This is far richer than a generic 'upload an image' statement.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is long but information-dense; every sentence contributes operational detail. It is top-loaded with the core purpose and then expands into necessary constraints. It could be slightly better structured with bullet points, but no sentence is wasted.

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?

The description is very complete for a tool with no annotations and no output schema: it covers input formats, size limits, URL behavior, storage lifecycle, and related tools. Minor gaps remain around the exact upload response shape and behavior on duplicate names, but the agent likely has enough to call the tool correctly.

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?

Although the schema already describes all three parameters, the tool description adds crucial semantics not encoded in the schema: 'Give exactly one of image_base64 or url,' the recommendation to prefer url above 10 KB, detailed url constraints, and the meaning of `name` as the identifier later passed to other tools. This materially improves an agent's ability to invoke parameters correctly.

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 action, 'Send an image to this hosted endpoint,' and clearly identifies the tool's role in the workflow: upload once, then pass the name as `path` to downstream image tools. It distinguishes itself from siblings by explaining that this is the upload step rather than a processing/manipulation step.

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?

It explicitly explains when to use image_upload versus other tools: 'There is no filesystem here, so instead of a path you upload the file once... and then pass its name as path.' It also gives concrete decision guidance between base64 and url inputs, including size thresholds and constraints, so an agent can select the correct invocation mode.

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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