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

Annotations only declare it is a non-destructive, non-idempotent write. The description goes well beyond that: collections start private, owner search reads current files while published bases are snapshotted, publication excludes private bases and later additions, every public read re-checks base publication, and withdrawn/private collections 404. It even documents the cache header ('private, no-store'). This is exactly the extra behavioral context the rubric rewards.

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 purpose is front-loaded in sentence one, which is good, but the remainder is a telegraphic stream of publication, access-control, and caching rules whose connection to a create operation is not always clear. Information is dense but not well structured or scoped to the tool's action.

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 still manages to convey visibility defaults, read semantics, and failure behavior (404), which is substantial. It does not say what a successful response contains (e.g., a collection identifier for later use), which is the main remaining gap for a create tool.

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 100%, so both 'name' and 'idempotency_key' are already fully documented in the schema (including the retry-after-failure semantics). The description adds nothing about either parameter, so the baseline of 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?

The first sentence states a specific verb and resource ('Create a private collection of base references') and immediately clarifies the core semantic that distinguishes it from copying tools: 'Collections store references, not copied content.' It does not explicitly differentiate from siblings like create_base or save_collection_base, which keeps it short of a 5.

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?

There is no explicit when-to-use guidance and no routing to alternatives such as create_base (creating a base) or save_collection_base (adding references to an existing collection). The usage must be inferred from the scope statement 'of base references,' which is minimal.

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