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

The annotations include idempotentHint=true and destructiveHint=false, indicating a non-destructive, idempotent operation. The description adds valuable behavioral context: it stores `currentAppId` and possibly `appToken`, defaults the auth mode to app-token under conditions, and notes that errors are deferred to the first app-scoped API call. This goes beyond annotations by explaining the session state mutation and error handling.

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 description is concise yet informative, with key information front-loaded. It avoids redundancy and presents the most critical behavioral effects (storing context, auth mode defaults) early, followed by error handling and related tools. Every sentence adds value.

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?

Given the tool's simplicity (3 parameters, no output schema, no nested objects), the description is adequately complete. It covers all necessary aspects: purpose, parameters, auth, errors, and relation to siblings. The only minor omission is explicit mention of how to retrieve a valid `appId` (though the parameter description covers that), so it is nearly complete.

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%, so the schema already documents all parameters clearly. The description reinforces the semantics of `appToken` and `authMode` by explaining their interplay (e.g., appToken defaults auth mode to app-token unless overridden), but does not add new meaning beyond that. Since coverage is high, a baseline 3 is appropriate.

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 clearly states the tool's purpose: to set the current app context for the session, enabling app-scoped tools to omit their `appId` argument. It uses specific verbs ('set') and resource ('current app context'), and mentions the effects on `appId` and `appToken`. While the name and title are somewhat generic, the description adds precise detail about the session context and its implications.

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 this tool: to set the current app context, and pairs it with `ethora-auth-use-app` as related. It also clarifies that no authentication is required to set the context, and that a non-existent `appId` is not validated here. This provides clear guidance on prerequisites and when to use it versus alternatives.

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