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

With no annotations and no output schema, the description carries the full burden of behavioral disclosure, and it discloses almost nothing. It does not say whether monitoring is a one-shot diff check or a long-running watch, what state it maintains, whether it polls, what it returns, or what side effects (if any) exist. The mechanics of 'monitor for changes' are entirely opaque.

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 description is short, but the 'Feed Monitor:' label is redundant with the tool name and the remainder is a tautology. Size is not the problem — substance is. No sentence earns its place because the only content sentence merely restates what the name already says.

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?

For a tool with two optional parameters, no annotations, and no output schema, the description is severely incomplete. An agent cannot determine what values to pass for 'feed' and 'input', what the tool returns, whether it blocks or is continuous, or how to interpret 'changes.' Nearly everything needed for correct invocation is missing.

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 technically 100%, but both parameter descriptions are circular ('Feed to process', 'Input to process') — they restate the parameter name without conveying meaning. The tool description adds no clarification, leaving the 'input' parameter genuinely ambiguous: is it a previous snapshot to diff against, a filter, or a query?

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?

The description 'Monitor a feed for changes' is a near-verbatim restatement of the name Feed Monitor; the only new information is the phrase 'for changes.' It fails to specify what kind of feed is meant (RSS, data stream, API endpoint?), what a 'change' looks like, or how this differs from siblings like x402-feed-normalize, x402-rss-parse, or x402-fetch.

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?

No guidance is given on when to use this tool versus its many siblings (x402-feed-normalize, x402-rss-parse, x402-web-retrieve, etc.), and no conditions, prerequisites, or exclusions are stated. The agent is left to guess the appropriate invocation context.

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