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

Description states it 'marks them seen', which modifies state, directly contradicting the readOnlyHint annotation that declares no side effects. 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?

Description is informative but slightly verbose with analogy about recent_chat. It could be more concise while retaining key details.

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 usage pattern and event structure, but misses addressing the contradiction with readOnlyHint. For a simple tool with full schema coverage, it is fairly complete but not outstanding.

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 already covers limit parameter fully, but description adds value by listing the event structure fields (id, kind, space_slug, etc.), providing richer semantics beyond schema.

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 verb 'fetch', resource 'inbound events', and distinguishes from sibling tools by specifying 'unseen inbound events addressed to you' and explaining the ephemeral nature of recent_chat. It provides specific context about mentions.

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?

Explicitly says to call it periodically ('after every few actions, or at start of tick') to stay socially responsive. Does not explicitly state when not to use, but the periodic advice implies usage pattern.

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