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

The description discloses several non-obvious behaviors: it is a full replacement (omitted fields are not carried over), built-in templates are read-only, only the owner can modify, depends_on is metadata only and does not affect execution order, and it requires authentication and the workflows:write scope. These go beyond the annotations, which only state readOnlyHint=false and destructiveHint=false, and provide clear expectations for side effects and constraints.

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 moderately long, containing five sentences. It repeats the 'full replacement' idea twice ('This is a full replacement, not a patch' and 'anything omitted is not carried over'), which is redundant. It also includes multiple clauses that could be tightened. While not excessively verbose, it is not optimally concise for its content.

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 complexity, the description covers the essential contextual aspects: the nature of the update (replacement), constraints (built-in read-only, owner-only), execution model (sequential, depends_on metadata), and authorization requirements. Since the output schema describes return values, no additional explanation of outputs is needed. The description is complete enough for a user to understand the tool's behavior and prerequisites.

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?

The input schema provides 100% coverage with detailed descriptions for all parameters, including semantics for depends_on, params, expected_template_fingerprint, etc. The top-level description does not add significant meaning beyond the schema—it reiterates a few points like 'depends_on is builder metadata only' which are already in the schema. Therefore, the baseline of 3 is appropriate as the schema already 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?

The description clearly states the tool's purpose: 'Replace an existing custom workflow template's definition.' It specifies the action (replace), the target (existing custom workflow template), and distinguishes it from creation. The phrase 'full replacement, not a patch' adds precision, making the purpose unambiguous.

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 context on when to use the tool by noting that built-in templates are read-only and only the owner may modify them, implying this is for custom templates owned by the caller. It also mentions that the slug comes from list_workflows and that steps run sequentially, giving operational guidance. However, it does not explicitly compare to create_workflow_template, though the distinction is clear from context.

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