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

Annotations already indicate readOnly, openWorld, idempotent, non-destructive behavior. The description adds valuable context: return structure (source, citation_uri, raw payload), mark_read side effect, polling suitability, and alternative access method. No contradiction with 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?

Five sentences, each earning its place. First sentence states purpose, subsequent sentences add detail on return values, filters, mark_read behavior, polling, and alternative access. No redundancy or fluff.

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 no output schema, the description covers return format, all parameter purposes (though unread_only is mentioned only in schema), and provides operational context (polling, alternative endpoint). For a read tool with optional parameters and rich annotations, this description is complete.

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 baseline is 3. The description adds meaning by explaining the effect of 'mark_read' (flags returned events as read), gives a concrete filter example ('sec_8k'), and clarifies 'since' as ISO timestamp. This extra context 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?

Clear verb 'pull' and resource 'fired events from your subscription feed'. The description states the tool's core function directly, but does not explicitly distinguish it from sibling tools like 'list_subscriptions' or 'recent_changes', leaving room for confusion.

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 usage context such as 'Polls work fine' and mentions an alternative endpoint for scripts/dashboards. However, it does not specify when not to use this tool or contrast it with alternatives, so the guidance is good but not comprehensive.

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