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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the bar is lower. The description still adds material context the annotations lack: pricing ($0.001 USDC per successful call via x402 on Solana) and an equivalent HTTPS endpoint, which matters for an agent deciding whether to pay. It doesn't say what the response body looks like, keeping it from a 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-loads the definition, then examples, then the input range, then the payment/endpoint metadata — a sensible ordering with little waste. The pricing and URL sentences are operational rather than semantic, but they earn their place for a paid tool.

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 two-integer predicate with no output schema, the description covers domain, semantics, and edge cases; 'Whether…' implies a boolean return. Only a one-word statement of the return type and response shape 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 0%, so the description carries the load for a and b; the predicate wording plus examples pin down exactly what each argument means and how they relate. The bounds restated in prose duplicate the schema's minimum/maximum, so the added value is the semantics, not the range.

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 precise predicate: 'Whether every 1 bit of a is also a 1 bit of b,' with three worked examples (3⊆7, 3⊄5, 0⊆0) that remove any ambiguity. No sibling in the list computes this relation, so the lack of explicit sibling differentiation is not a gap.

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?

The definition plus examples make it obvious when this tool applies (subset testing on bitmasks), and the 0–999999999999999 range tells the agent the input domain. It gives no explicit exclusions or alternatives, but no nearby competing tool exists, so a 4 rather than 5.

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