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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is free; the description goes further by disclosing tier-gated behavior (free tier returns complete records only for sample events and classification facts otherwise, full tier returns every field) and by defining the semantics of the returned `date` field. It stops short of covering failure behavior for an unknown ID, so it is strong rather than exhaustive.

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 tight sentences ordered by usefulness: what it returns, when to use it, the ID format, then the tier caveat. The opening field enumeration is slightly listy but each element informs the agent about coverage, so little is wasted.

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?

With no output schema, the description carries the burden of describing the return payload and does so via the field list plus the free/full tier distinction. Combined with the routing guidance and ID format, an agent has everything needed to call it correctly.

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?

Only one parameter and schema coverage is 100%, so the schema already documents event_id including the zero-padded format. The description's 'Pass `event_id` as the zero-padded string (e.g. "06", "141")' largely restates the schema rather than adding new meaning — correct baseline.

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?

States a specific verb+resource (retrieve one event by ID) and enumerates exactly what the record contains (classification, assessment, sources, industry tags, ENTs, bloc analysis, tier rationale). It is clearly distinguishable from the sibling get_event_stack and from search_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?

Explicitly states the precondition ('Use when you already hold an event ID') and names the alternative for the opposite case ('to find IDs, use `search_events`'). No inference is required to pick between the two tools.

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