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

The description adds substantial value beyond the annotations: it discloses partial-update behavior (omitted fields unchanged), requires user-auth and ownership, and enumerates specific error conditions with status codes. This gives the agent a precise mental model of side effects and failure modes.

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 compact and front-loaded: purpose and field list first, then partial-update behavior, then auth and errors. Every sentence carries operational information, with no filler or repetition of schema details.

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 six-parameter mutation tool with no output schema, the description covers the essential operational context: what fields change, partial-update semantics, auth requirements, ownership constraint, and all relevant error paths. An agent has enough information to call the tool correctly and interpret failures.

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 schema already documents each parameter thoroughly. The description still adds useful context by framing all listed fields as mutable app attributes and stating that omitted fields remain unchanged, which clarifies how the optional parameters behave collectively.

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 states a specific verb ('Update'), a clear resource ('an app the caller owns'), and enumerates the exact mutable fields. It also clarifies the partial-update semantics, making the tool's purpose unambiguous and easily distinguishable from app create/delete/select siblings.

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 makes the usage context clear: the caller must own the app and have an active user-auth session, and only mutable fields are affected. It does not explicitly name alternative tools or state when not to use it, but the ownership and field-scope guidance is enough for an agent to select it appropriately.

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