user_sessions

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

Beyond the readOnlyHint annotation it adds genuinely new behavioral facts: the [READ] marker, the exact return envelope ({"sessions": [...], "returned": N, "truncated": false}), and the guarantee that the IdP returns the user's whole session set so results are never partial. That completeness guarantee is information the annotation does not carry.

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?

Front-loaded with the resource and a [READ] tag, then a compact Args block and a single return-value sentence. Every sentence earns its place and there is no filler, though it is slightly longer than strictly needed for two documented params.

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 compensates well by spelling out the return envelope and the completeness guarantee, so an agent knows what comes back. The only gap is the unexplained max_results and its relationship to the claimed "always complete" listing.

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 0%, so the description must carry the load; it documents user_id (source: list_users) and target (IdP name, omit for default), which is real added meaning. However max_results is never mentioned, and it is the one parameter that interacts with the description's "always complete / truncated: false" claim, leaving an ambiguity about capping.

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?

It names the resource and its scope precisely: "A user's active sessions (id, IP, start/last access, clients)", which is enough to distinguish it from client-scoped siblings like client_sessions. The action verb (list/fetch) is implied by the parenthetical field listing rather than stated, but an agent can still tell what it returns.

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 gives useful precondition guidance for parameters ("user_id: User id, from list_users", "omit for the default" target), which tells the agent how to supply inputs. It never states when to choose this tool over client_sessions or revoke_user_sessions, so usage context is implied rather than defined.

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