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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the bar is lower, and the description still adds real context beyond them: hosting origin ('Published on the storage origin, never on 402.com.tr'), retention limits, cost ('$0.01 per call over x402 on Base'), and auth ('send a prepaid x-credit-token header... No API key required'). It does not address what happens on republishing the same text, whether the URL is public/guessable, or the exact expiry behavior, so not a full 5.

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?

Front-loaded with the core action and sibling distinction, and each subsequent sentence (retention, host, price, auth) carries decision-relevant information. It is on the long side with a few trailing negatives ('no scripts and no external requests', 'no free tier on this tool') that could be tightened.

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?

An output schema exists, so return values need not be explained, and the description covers cost, auth, retention, and hosting origin for a 4-parameter tool. Gaps remain around privacy/access to the produced URL and republish semantics, which matter for a publishing tool.

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 description coverage is 100%, so baseline is 3; the description adds meaning by constraining ttlDays to a concrete '1-30 days' range that the schema field ('Retention in days (optional)') leaves open, and by restating that text is required. It does not elaborate on format or title beyond the schema.

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?

States a specific verb+resource ('Turn a report into a link... Send Markdown (or HTML) and get back a URL') and immediately distinguishes itself from the closest sibling: 'file-slot is for bytes it will fetch back, this is for the report somebody has to read.' An agent can place this tool without opening either schema.

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?

Explicitly names the alternative (file_slot) and the condition that selects between them (machine-fetched bytes vs. human-read report). It also states the retention window (1-30 days) and the pricing/auth model, which are decision-relevant preconditions for calling it.

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