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

Annotations already declare read-only, non-destructive, closed-world safety. Beyond that the description adds ordering ('Newest first'), an auth requirement ('authenticated feed read'), and a paging constraint by cross-reference, which are real behavioral facts not in the annotations. Return shape and exact cap values are not disclosed, but the schema carries the cap.

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?

Four short sentences, front-loaded with the identity of the tool and the core constraint. The 'Same paging caps as list_my_activity' clause forces a cross-reference instead of stating the cap directly, a minor structural cost.

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 5-param read tool with no output schema and full schema coverage, the description supplies the missing pieces: target identity, ordering, and auth. Pagination specifics are delegated to a sibling rather than stated, which is the only notable 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 coverage is 100% so the baseline is 3, but the description earns a bump by stating 'Requires username or userId' — the schema itself marks zero required parameters, so this is genuine added meaning that clarifies the effective requirement.

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 verb (list) plus two resources (pours/activity) scoped to 'another user', which directly distinguishes it from the sibling list_my_activity. An agent can pick between the two without opening either schema.

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?

Gives clear context: use this to read another user's activity, and it requires either username or userId. It references list_my_activity for paging caps but does not spell out when to prefer one over the other or any exclusions, so it stops short of full routing guidance.

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