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

The description explicitly states that setting mark_read:true 'flags returned events read' and affects subsequent calls, implying a state mutation. This directly contradicts the annotation readOnlyHint=true. Although the description adds useful return-format details, the contradiction is a serious inconsistency, warranting a 1 per the rubric. No other disclosure can mitigate this mismatch.

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?

The description is four sentences, front-loaded with the main purpose. It includes necessary examples and the alternative endpoint without excessive verbosity. It earns a 4 rather than 5 because the last sentence about the feed URL could be seen as slightly tangential for an agent using the tool, but it is still useful.

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 read-oriented tool with no output schema, the description adequately explains the return format (source, citation_uri, payload) and includes operational guidance (polling, endpoint). The lack of pagination details is minor given the schema's limit/default, and the contradiction with annotations lowers the overall completeness slightly, but the description alone is fairly comprehensive.

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. The description adds value beyond the schema by explaining the semantics of mark_read ('so the next call only shows newer ones') and giving an example type filter. It does not cover all params (e.g., unread_only), but the additional context for key parameters justifies a 4.

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 states the tool's verb and resource: 'Pull fired events from your subscription feed.' It specifies the scope (recent alerts, persisted feed) and gives examples of filters. However, it does not explicitly differentiate from sibling tools like list_subscriptions, so it misses the 'distinguishes from siblings' bar for a 5.

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 provides clear context for use, including filtering options and the polling behavior ('Polls work fine'). It also offers an alternative for scripts/dashboards via the direct endpoint, giving the agent a decision point. However, it doesn't explicitly mention when not to use this tool or name sibling alternatives, so it falls short of a 5.

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