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

Annotations already flag destructive and idempotent, but the description goes well beyond them: it warns that previous values are not kept and cannot be restored from the API, clarifies the partial-update semantics (omitted fields unchanged), and enumerates auth mode plus concrete error codes (401/403/404/422) with a validation example. This is exactly the extra context annotations cannot carry.

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?

Front-loads the destructive warning, then the field list, then requirements/auth/errors — a sensible ordering for a mutation tool. Some content (error codes, per-field format rules) duplicates the schema, which is mild redundancy rather than bloat.

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 7-parameter mutation with no output schema and no required fields, the description covers irreversibility, partial-update behavior, ownership requirement, auth mode, and failure modes. Nothing an agent needs to invoke this safely 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?

Schema description coverage is 100%, so every parameter is already documented in the schema, including the botStatus vs. prompt distinction and the appDescription deprecation note. The description's field list largely restates that; baseline 3 applies when the schema does the heavy lifting.

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 and resource ('Update mutable fields on an app the caller owns') and enumerates exactly which fields are mutable (displayName, domainName, appTagline, primaryColor, botStatus). The scope is distinct from siblings like ethora-app-create and ethora-app-list, so an agent can route without opening the 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?

Gives real usage context: confirm changes with the user first, and the `appId` must come from `ethora-app-list` or `ethora-app-create`. It also acknowledges the implicit app from `ethora-app-select`. It stops short of an explicit when-not or a named alternative tool, so it is strong but not fully routing.

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