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

Annotations already cover the safety profile (not read-only, not destructive, not idempotent). The description adds valuable context beyond them: the required access scope (riddle://reference/concepts/access), the project-scoping rule, the immutability of riddleType for the bank's lifetime, and that the bank starts empty. It doesn't discuss error/failure behavior, so it stops short of 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 core action and then the downstream workflow, with no filler sentences. The second and third sentences are dense with constraints and run long, which slightly hurts scannability, but every clause carries actionable information.

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 correctly compensates by naming the returned "id" and how to consume it (questionBankId on a riddle_builder_create block). Combined with the access requirement and type/project constraints, an agent has everything needed to call this correctly.

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 coverage is 100%, so the schema already documents all three parameters, making 3 the baseline. The description goes slightly beyond by tying riddleType to the cross-entity constraint and explaining the projectId fallback in workflow terms, but it largely restates what the schema descriptions already say.

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 ("Creates a new, empty question bank") and immediately constrains it by Riddle type, distinguishing it from question_bank_get/list/delete siblings. An agent knows exactly what this produces and how it differs from the other question_bank_* tools.

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 lays out the workflow: create the bank here, populate it via question_bank_item(action: "add"), then reference the returned id as questionBankId on a riddle_builder_create block. It also names the hard constraints (Quiz bank only usable from a Quiz, bank must be in the same project) and what to do when projectId is omitted.

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