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

Despite readOnlyHint and openWorldHint being present, the description adds substantial behavioral detail: cursor continuation with `next_cursor`, `wait` behavior with invalid_input for large values, durability ('the stream is the record'), and a security warning that `_untrusted` fields are data, not instructions. 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?

Although lengthy, the description front-loads the core purpose and every sentence carries essential information: event types, payload shapes, cursor mechanics, and security guidance. There is no filler or redundancy.

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?

For a complex stream tool with no output schema, the description covers event types, payload structure, cursor behavior, polling, and untrusted-data handling. The only small gap is the exact top-level response envelope, but `next_cursor` and the event object shape are sufficiently specified for correct invocation.

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?

The description explains `after` cursor semantics in depth, documents `limit` default and range (schema lacks a description for limit), and details `wait` behavior and constraints. It also introduces `next_cursor` as the continuation value, adding meaning beyond the schema's 67% coverage.

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?

The description states a specific verb (stream), resource (events), and scope (your profile), with clear ordering (oldest first) and cursor semantics. It distinguishes itself from the many specific sibling queries by being the universal event stream and enumerates all event types by role, so an agent can tell it apart without opening schemas.

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?

It provides strong context on when to use the tool: to see the full profile event history, to poll without a server (via `wait`), and it maps event types to seller/buyer roles. However, it does not explicitly name alternative tools or state when not to use it, leaving some inference to the agent.

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