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

Annotations already cover read-only safety, but the description adds valuable behavioral detail: the first sources are limited to 3 to 90 days, pages are returned in order with their times, and event values are grouped per currency. These are useful traits beyond the annotations, though auth and response-size behavior are not covered.

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?

The description is front-loaded with the core action and remains a single dense sentence. It is appropriately sized, though cramming several return-value details into one sentence makes it slightly less scannable.

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?

Given that an output schema exists and annotations cover safety, the description is largely complete: it identifies the id format and summarizes the returned session details. The main remaining gap is guidance on when to choose this tool over its sibling search/list tools.

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 the baseline is 3. The description repeats that session_id can be a ses_… or VS… id, but this is already documented in the schema, and it adds no meaning for container_id or server_name.

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 uses a specific verb and resource: 'Returns one session by its id'. It also distinguishes the tool from siblings like list_sessions and search_sessions by emphasizing a single session and naming the fields sourced from search_sessions.

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?

Usage is implied: fetch a session by id and use its event ids with get_event. However, the description does not explicitly state when to use this tool versus list_sessions, search_sessions, or query_sessions, and gives no exclusions.

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