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

Description states 'Set mark_read:true to flag returned events read' which is a state-changing operation, directly contradicting the annotation readOnlyHint:true. This is a clear contradiction and warrants the lowest score.

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 compact, front-loads the core action, and every sentence adds meaningful detail without fluff. It efficiently conveys filters, return payload, and alternative access.

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?

Despite having no output schema, the description covers return format (source, citation_uri, raw payload), filtering options, mark_read behavior, polling, and an alternative endpoint—making it highly complete for an agent to understand the tool's behavior.

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 covers all 5 params, but description adds value by giving a filter example ('sec_8k'), explaining the effect of mark_read on future calls, and clarifying polling suitability—going 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?

Description clearly states 'Pull fired events from your subscription feed' with a specific verb and resource, and distinguishes itself from siblings like list_subscriptions which list subscriptions, not events. The purpose is unambiguous.

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?

Provides explicit usage guidance by noting 'Polls work fine' and offering an alternative access method via HTTP endpoint for scripts/dashboards. This gives clear direction on when to use the tool vs. the alternative.

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