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

With no annotations, the description carries the full burden and handles it well: it discloses the quota error code (quota_caller), that the call 'never runs,' and that this tenant's own calls are unaffected. These are exactly the behavioral facts an agent needs beyond the raw schema.

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?

Three compact sentences with no filler: the core behavior is front-loaded, followed by the precondition and the key side-effects. Every sentence earns its place.

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 configuration tool, the description covers what it does, when it can be used, what happens on violation, and what it does not affect. It does not describe the success return shape, but no output schema exists and the invocation behavior is otherwise fully specified.

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 the baseline applies. The description reinforces that calls_per_day counts 'successful calls' per UTC day and ties the tool parameter to the sharing precondition, but it does not add detailed parameter-level semantics beyond the schema, which is acceptable.

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 opens with a specific verb and resource: 'Cap how many successful calls a caller tenant may make per UTC day into one of this tenant's shared tools.' This unambiguously defines the operation and distinguishes it from the sibling caller_limit_remove without conflating it with general sharing 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?

It provides a clear precondition: 'The tool must already be shared,' so an agent knows this is a post-sharing step and should route to host.tool_share first if that precondition fails. It does not explicitly enumerate alternatives or when-not-to-use cases, but the constraint is specific enough to guide invocation.

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