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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description's job is to add what they don't: that isQuickCreate templates are merged into the same list, that results are not paginated so total is an exact count, and that build configuration is excluded. Missing only auth/scope caveats beyond the schema's note on API-key scoping.

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?

Dense but front-loaded: scope and the sibling exclusion come first, then quick-create behavior, then the return shape. Every clause carries information, though the formatting as one run-on paragraph with inline literals is slightly harder to scan than it could be.

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 steps in and enumerates the returned fields (id, title, type, blocksCount, image, icon, createdAt, riddle, isPublic, isQuickCreate) plus the total envelope, and explains the non-pagination semantics and where the build configuration lives. Nothing an agent needs to call this correctly is absent.

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% and both parameters are fully documented there, including the type enum values and the projectId default behavior. The description only restates that type filters by Riddle type and adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 (Lists) and resource (templates of a project or your personal ones), and explicitly carves out what it is NOT: Riddle's public ones, which it names as returned by riddle_template_public_list. An agent can distinguish it from riddle_template_create, riddle_template_get, and riddle_template_public_list without opening any schema.

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 names the alternative (riddle_template_public_list) for public templates, and routes onward: read build config with riddle_template_get, or hand the id to riddle_template_use. It also clarifies that there is no separate listing for quick-create templates, closing a likely agent assumption.

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