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

The description explicitly states that setting mark_read:true flags events as read and affects future calls, which is a state-modifying behavior. This directly contradicts the annotations' readOnlyHint=true. Per the rule, a description contradicting annotations scores 1. This is a serious inconsistency.

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 a 5-sentence paragraph, but every sentence carries useful information: purpose, return contents, filtering, mark_read, polling, and alternative endpoint. It is front-loaded and efficient, though slightly longer than the highest-performing examples.

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?

Given 5 optional parameters and no output schema, the description is remarkably complete: it explains return payload, filtering options, mark_read side-effect, polling suitability, and an alternative access URL. It doesn't cover error cases or edge behaviors, but the core usage is well explained.

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 by giving an example for type (e.g. 'sec_8k'), explaining mark_read semantics, and clarifying the since parameter as ISO timestamp. This goes beyond the schema descriptions.

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 purpose: 'Pull fired events from your subscription feed.' It uses a specific verb (pull), identifies the resource (subscription feed), and mentions return contents. It distinguishes itself from siblings like list_subscriptions by focusing on alerts/events.

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 gives usage context (polling, filtering, mark_read) and even mentions an alternative HTTP endpoint for scripts/dashboards, but it does not explicitly contrast with sibling tools or state when to use this tool over alternatives. It implies usage for reading alerts but lacks explicit exclusion criteria.

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