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

Annotations already indicate destructive and non-read-only behavior, so the bar is lower. The description adds useful constraints: 'text only, 1.5 MiB max' for the script, and it implies that the operation is a full replacement. It does not elaborate on side effects beyond what annotations cover, but the added size/format constraints provide extra transparency.

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: two sentences that lead with the core purpose, then provide guidance and key constraints. There is no filler or repetition of schema details. It is well-structured and front-loaded.

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 has 6 parameters and no output schema, the description covers the main purpose, alternatives, and key parameter constraints. However, it omits context about the approval workflow (e.g., when `approvalId` or `sessionToken` are needed) and does not describe return values or success behavior. It is adequate but not fully comprehensive.

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 50%, so the description needs to compensate. It does clarify that `script` must be a full ES module and size-limited, and it names the required parameters. However, it does not explain the semantics of `tenantId` and `workerName` (which lack schema descriptions), leaving some ambiguity. Overall, it adds some value but not comprehensive compensation.

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 action ('Replace the server-side code of an existing roost') with a specific verb and resource. It distinguishes itself from siblings by explicitly mentioning `upload` and `convert` as alternatives for different use cases, making the tool's unique scope evident.

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 provides clear usage guidance: it warns that this is 'Advanced' and most agents should use `upload` or `convert` instead. It also specifies the required parameters (`tenantId`, `workerName`, `script`), giving direct instructions on when and how to invoke the tool.

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