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

Beyond the readOnlyHint/openWorldHint annotations, it discloses ordering (newest first), the time-window bounds (1-30 days, default 7), that responses are signed, and the exact cost model ($0.02 USDC per call via x402 on Base or Solana). The payment/auth requirement is a critical behavioral trait not captured in annotations.

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-loads the resource and coverage, then appends behavior and pricing. Efficient with no filler, though it is a single run-on sentence that could be broken for scannability.

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 no output schema, the description does the heavy lifting by naming the event types and counts returned. Combined with the pricing and time-window details, an agent has enough to call it correctly, though response shape details remain inferred.

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 0%, so the description must carry parameter meaning, and it does: days is given a default (7) and range (1-30), and ecosystem is explained as 'one ecosystem or all,' matching the enum values enumerated up front. It could note the expected string format for days, so not a full 5.

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 (watch) and resource (supply-chain events across popular packages), scopes coverage precisely (8,000 most-used packages on npm, PyPI, crates.io, Go), and enumerates event types. This clearly distinguishes it from the sibling packages_check, which the agent can infer is a narrower per-package lookup.

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?

Implies usage as a broad newest-first feed with an adjustable time window, but never says when to prefer it over packages_check or the other sibling tools. No explicit exclusions or alternative-routing guidance is given.

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