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

Annotations already cover read-only, idempotent, non-destructive and closed-world, so the bar is lower, but the description still adds real value: newest-first ordering, the fact that sessions are derived from activity and never started/ended, and the meaning of 'unread' relative to your last acknowledged change. It stops short of stating result-set size limits or what happens with an expired cursor.

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?

Purpose and ordering are front-loaded, but the middle clause becomes a dense field dump ('actions, item title and id, versions with numbers, rows, handoff notes') that duplicates what the output schema already defines, and the whole text is one sprawling sentence that could be split or trimmed.

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 two-parameter read with full annotations and an output schema, this is largely complete: ordering, derivation, unread semantics, and pagination are all addressed. The only remaining gap is the absence of any pointer to the sibling tool that shows the changes behind an unread mark.

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 50% — workspaceId is documented in the schema but cursor has no description there. The line 'Continue with cursor' supplies the missing semantics by telling the agent cursor is a pagination continuation token, which the schema alone would not convey. Baseline would be 3; the compensation for the undocumented parameter raises it.

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 opens with a specific verb and resource ('Read recent sessions in a workspace, newest first') and clarifies that sessions are computed from activity rather than created ('nothing is started or ended'). The domain term 'session' stays somewhat abstract and no sibling (e.g. workspace_changes, activity) is named as the contrasting tool, so an agent gets the gist but not a crisp boundary.

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 context is implied rather than stated: 'recent sessions' plus 'Continue with cursor' tells the agent this is a paginated read, and the unread note points at workspace_changes_ack as a follow-up. There is no explicit 'use this instead of X when Y', so the agent must infer when to pick this over workspace_changes or activity.

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