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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false), so the description adds real value by disclosing the account-gating behavior and the exact failure sentinel 'not_available'. It does not say whether the takeaway is persisted server-side or merely returned, which is the one behavioral detail still missing for a create-verb tool.

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?

Three sentences of roughly equal weight: trigger first, then what is produced, then availability. No restatement of the title and no filler.

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 3-parameter tool with no output schema, the description covers the trigger, the output format and the failure mode. The only substantive hole is the undocumented 'kind' enum branching, which is what an agent most needs before calling with kind='template'.

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 67% and the uncovered parameter is the important one: the 'kind' enum ('takeaway' vs 'template') has no description and the description never explains which value to choose or that 'template' changes the required inputs. The 'session' and 'template_id' semantics are already documented in the schema, so the description adds almost nothing there.

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?

Specific verb and artifact: 'Composes a markdown takeaway from this journey session', followed by the exact contents (what the user asked, key points, stops visited). That is far more concrete than the sibling names imply and none of the siblings produce a takeaway. It stops short of naming an alternative tool, so it is clear but not sibling-differentiating.

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?

'Use when the user asks for a summary to keep' gives an explicit trigger condition, and the connected-account caveat tells the agent when the call will fail. There is no statement of when NOT to use it, e.g. for a running progress check, which would have earned a 5.

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