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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds that this is a navigation/bootstrap entry point returning workspace name, sites and a starting briefing, but since an output schema exists, the return-value detail is largely redundant rather than additive.

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?

Two sentences with the action front-loaded and no filler. The middle clause enumerating briefing/Decisions/performance/changes is slightly list-heavy but earns its place by conveying what the opened app contains.

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 rich annotations, full schema coverage, an existing output schema, and a single optional parameter, the description supplies enough to call the tool correctly. Only the relationship to sibling read tools remains unstated, which is a minor gap given the low complexity.

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% and the site parameter already documents its domain-or-id format and its default to the newest active site. The description's "of a site" phrase reinforces the parameter's role but adds no syntax or selection semantics beyond the schema, so the baseline 3 applies.

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 and resource ("Opens the OneLence app") plus the scope of what the user browses: briefing, Decisions, performance, recorded changes. It is distinguishable from data-fetch siblings like onelence_get_briefing or onelence_get_performance by framing itself as the app entry point, though the boundary with those tools is only implied.

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?

"Hosts open it from their navigation" gives a contextual hint about who calls it and when, which is more than nothing. However, it never states when NOT to use it or explicitly routes the agent to onelence_get_briefing / onelence_get_performance for targeted reads instead of opening the whole app.

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