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

Goes well beyond the annotations: it discloses that setting a source replaces the other one, that re-setting a broken source repairs it, that already-kept meetings are preserved, that reading happens at once, and that it is owner-only. The replacement behavior is consistent with destructiveHint=false and idempotentHint=true, so there is no contradiction.

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?

The core action is front-loaded and every clause carries information (source semantics, replace behavior, owner restriction). The dense em-dash chain makes it slightly heavy to parse, but there is little pure 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 2-param mutation tool with no output schema, the description covers the source options, switching behavior, and authorization. Minor gaps remain around conditional requirement of folder and error handling, but nothing essential for correct invocation is missing.

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?

Adds meaning beyond the schema for the enum: it explains what «granola» (read via the workspace's Granola key) and «a-folder-of-files» (Drive folder, one text file per meeting) actually pull in. The folder param is largely already covered by its schema description, so it is useful elaboration rather than fully compensating for the 50% coverage.

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 (Set) and resource (the one source of the workspace's meeting records) and enumerates both valid values with their meaning. An agent can tell this apart from the related save_the_granola_key / remove_the_granola_key siblings without opening any 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?

Clearly explains the two selectable sources and the switching semantics ('Setting one replaces the other, and setting a source that stopped working makes it work again'), giving strong context for when to call it. It stops short of explicitly naming the alternative tools (e.g., save_the_granola_key) or excluding cases, so it is clear context without explicit alternatives.

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