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

Beyond the readOnly, idempotent, and non-destructive annotations, the description discloses the error behavior (returns an error object rather than raising a protocol error), the fact that kits are not sold standalone, and that All-Access is how a caller actually unlocks a kit. This adds meaningful operational context beyond the 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?

The description is front-loaded with the core purpose, then provides return shape, usage routing, error behavior, and safety in a logical order. Every sentence adds necessary information; there is no filler or repetition of schema content.

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 zero-parameter read-only listing tool, the description is complete: it covers the exact output shape, subscription semantics, when to use it, which siblings to use instead, error behavior, and retry safety. The output schema and annotations further support completeness.

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?

The tool has zero parameters, so the baseline is 4. The description reinforces this with 'Takes no arguments' and goes further to explain that even malformed input is handled gracefully via an error object. Nothing more is needed.

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 names a specific verb and resource: 'List the 12 themed kits with pricing and member products.' It also explicitly distinguishes itself from get_full_kit and search_catalog, so an agent can select it without confusion.

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 description gives direct usage guidance: 'Use when the caller asks about bundles or bundle pricing' and explicitly says what not to use it for, naming search_catalog for individual products and get_full_kit for full kit contents. It also states that retrying is safe after correction.

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