get_activities

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

With no annotations, the description carries the behavioral burden. It adds meaningful context beyond the schema: this is intentionally cheap, acts as a sync gate, and its `all` value indicates whether changes occurred. It does not discuss auth or rate limits, but the read-only and lightweight nature is strongly implied.

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?

Two short sentences with no filler. The core purpose is front-loaded, and the second sentence earns its place by explaining the tool's strategic role in syncing.

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 zero-parameter tool with an output schema available, the description is complete enough. It tells the agent what the tool provides, why it should be called, and how to interpret the key signal (`all`) to decide whether further fetching is needed.

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?

The tool has zero parameters, so there is no parameter ambiguity. Baseline for zero-parameter tools is 4, and the description's mention of `all` refers to the response payload rather than input, which is appropriate.

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 clearly identifies the resource and output: timestamps of the user's most recent list changes. It is not a tautology and is easily distinguished from sibling tools like get_library or get_ratings, though it uses a noun phrase rather than an explicit verb like 'returns'.

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 explicitly frames the tool as 'the cheapest call in the API' and 'the gate for every sync,' telling the agent exactly when to invoke it. It also gives a concrete when-not condition: if `all` has not moved, nothing needs fetching.

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