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

Annotations already declare readOnlyHint/idempotent/non-destructive, and the description earns extra credit by explaining the mechanism: conversion and shrinking happen "in their own browser, so files are never uploaded," and the rules are surfaced in the chat. That resolves why a link-creating tool can be read-only and tells the agent what the recipient experiences. It does not cover rate limits, link lifetime/expiry, or what the returned link looks like.

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

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

The what-it-produces sentence comes first and the concrete example is front-loaded, which is the right order. The final two sentences overlap with earlier content (rules shown to the uploader is restated), so a sentence could be merged without loss.

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

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

With 16 parameters, zero required fields, and no output schema, the description should say what a rule-less invocation produces and roughly what the tool hands back. It explains the recipient-side behavior well but leaves the agent unsure whether calling it with no arguments is valid or meaningful, and says nothing about the shape of the returned link.

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

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

Schema coverage is 69%, so the baseline is 3, and the description contributes mainly through the worked example ("PDF or JPG, up to 2 MB, named Lastname_ID"), which maps to types, max_kb, and file_name. Half the parameter surface — width/height/square, min_kb, min_width, min_height, max_pages, max_files, for/what/note — is left entirely to the schema, and the description does not explain interactions such as width requiring height.

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

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

"Make a FileFleet link that carries a form's upload rules" states a concrete verb (make) and a concrete artifact (a link bundling upload rules), and the example rule string clarifies what "rules" means. It never names or contrasts with the available siblings (check_file, find_upload_requirements), so an agent must infer the boundary itself.

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

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

"Use it when someone has to upload files to a form, or collects files from other people" gives an explicit triggering condition in plain terms, which is stronger than most. It stops short of exclusions or naming alternatives, so there is no stated case where an agent should pick a sibling instead.

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