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

With no annotations provided, the description carries the full burden of disclosure, and it does well: it states that the tool returns success immediately without opening the viewer when a saved session is valid, and it flags force_reconnect as destructive and irreversible in effect. It omits details such as how long the viewer stays open, what happens if the user abandons sign-in, or what a failure looks like, which leaves some operational gaps.

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?

Four short sentences, front-loaded with the scoping rule, then the no-op behavior, then the prerequisite and the destructive caveat. No filler, and the ordering matches the order in which an agent needs the information.

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, non-destructive-by-default auth tool with no output schema, the description covers purpose, preconditions, and the success case. It does not describe the failure modes or the interaction flow after the viewer opens, which is a modest gap.

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 coverage is 100%, so the baseline is 3. The description goes further by explaining the intent behind force_reconnect: it wipes the saved cookie and should be used only on explicit user request, which reinforces the schema's own warning and clarifies the decision rule.

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 and resource: it opens the Google Photos sign-in. It also says it is a no-op when the session is still valid, which distinguishes it from a plain auth open. However, it tells the agent to call "session_status" while the sibling tool is named "check_session", so the routing hint does not line up cleanly with the actual tool list.

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 description explicitly states when to use the tool (only when needed, and after a session check) and when not to use it (do not set force_reconnect unless the user asks). It also gives the alternative to try first (the session check) and a precondition for the destructive path.

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