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

Description states that mark_read mutates state (flags events read), contradicting the readOnlyHint=true annotation. This is a critical inconsistency that misleads about side effects.

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 sentences, each earning its place: purpose, return format, filtering/mark behavior, alternative access. Front-loaded with primary purpose. No 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?

Covers return structure, polling suitability, and alternative endpoint. No output schema, so description compensates. Lacks details on authentication or rate limits, but annotations imply open access.

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%, but description adds valuable context beyond schema: explains type format (e.g. 'sec_8k'), ISO timestamp for since, and effect of mark_read. Adds meaning beyond parameter names/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?

Clearly states it pulls fired events from subscription feed, specifies returned fields (source, citation_uri, raw payload), and mentions filtering options. Distinct from sibling tools like list_subscriptions.

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 filtering guidance (type, since), describes mark_read behavior for polling, and notes alternative access via URL. Lacks explicit when-not-to-use but effectively guides usage.

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