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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=false), and the description adds genuine behavior: the tie-break rule for equal creation times, pagination continuation via meta.next_offset, and the volatility caveat "Results can change between requests." It stops short of describing auth or filter-combination internals, but goes well beyond the annotations.

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?

Front-loaded and mostly efficient, but "Equal creation times use descending ID order." is duplicated verbatim, wasting a sentence. That redundancy is a real structural flaw in an otherwise well-ordered description.

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?

An output schema exists and annotations carry the safety profile, so the description only needs to cover scoping, ordering, filtering and pagination — which it does. An agent has everything required to call this correctly.

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 schema already documents all five parameters including defaults and the tag_mode enum, making 3 the baseline. The description restates defaults (limit 50, offset 0, max 100) and adds only the continuation instruction "Continue with meta.next_offset and the same filters; stop when it is null," which is marginal added value.

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?

Specific verb+resource ("List Live Activities sent from this account") with scope, ordering ("newest first") and returned fields declared. It is clearly distinguishable from get_live_activity and the stream siblings.

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 states two use cases (review recent activity, find an activity_id) and routes the agent to alternatives by condition: get_live_activity for one known activity, set_live_activity_stream and other stream tools for changing a running activity.

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