Count Collections

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds that the count is scoped to collections accessible to the current user, but does not disclose details like whether empty collections are counted by default or how the filter affects results.

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?

A single sentence that front-loads the operation, resource, and scope with no wasted words. It is exactly as long as needed for the tool's simplicity.

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 simple read-only count tool with annotated safety and fully described parameters, the description is mostly complete. It states the result domain ('total number') and the scope, but with no output schema it leaves the exact response representation unstated, which is a minor gap.

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 parameters are already documented in the input schema. The description adds no extra meaning about the parameters, and the schema's 'Filter string' is terse, but the description does not need to compensate for a coverage gap.

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 operation ('get the total number') on a specific resource ('collections') and defines the scope ('accessible to the current user'). It is immediately distinguishable from sibling count tools like coll_count_docs and coll_count_find_documents by naming collections as the counted entity.

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 clearly implies this tool is for obtaining a count rather than a list or detailed collection data. It does not explicitly name alternatives or state when not to use it, but the context is clear and the scope is well-defined.

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