Approve session plan

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

Annotations already carry the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), so the bar is lower. The description adds that this is a state transition for awaiting-approval sessions, which is consistent with the annotations. However, given openWorldHint=true, it neither discloses post-conditions (what state the session reaches after approval, whether approval triggers plan execution) nor potential side effects — a real gap for a mutating action.

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?

A single eight-word sentence with zero filler. The core verb ('Approve') comes first, and the scoping condition ('awaiting plan approval') follows immediately. Every word earns its place.

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 one-parameter tool with a straightforward action, the description is mostly adequate. But with no output schema and openWorldHint=true, the agent is left uninformed about what the approval does (state transition, triggering of execution, return value). Given the richer workflow implied by siblings (monitor_session, send_message, extract_pr_from_session), a sentence on the post-condition would meaningfully complete it.

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% — the single required session_id parameter is already documented in the schema ('The Jules session ID'). The description adds only marginal semantic value by constraining that the session must be in an awaiting-approval state. Baseline 3 is appropriate since the schema does the heavy lifting and the description adds no syntax or format detail.

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 ('Approve') and resource ('plan for a session'), and the qualifier 'awaiting plan approval' pins down the exact session state to which it applies. This clearly differentiates it from siblings like jules_get_session, jules_send_message, and jules_create_session — an agent can tell what this tool does and what it's not without opening the schema.

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?

The target condition is implicit in 'for a session awaiting plan approval,' which tells the agent when the tool is relevant. However, there is no explicit statement about checking session state first (e.g., via jules_get_session), no exclusions (e.g., what to do if the session isn't awaiting approval), and no named alternatives. Usage context is present but mostly implied rather than stated.

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