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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe, repeatable read. The description adds value by noting the operation is 'FREE' (cost implication) and by specifying the content of the expanded step, which is not captured in the annotations. There is no contradiction.

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 three sentences, all purposeful. It front-loads the key 'FREE.' and the core action, then explains the context and prerequisite. There is zero fluff, and every sentence earns its place.

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 read-only, idempotent tool with full schema coverage and strong annotations, the description is complete. It explains what the expanded step will contain, satisfying the lack of an output schema. The prerequisite of the same share code and step id is noted, so nothing essential for a correct call 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 the schema already documents both parameters. The description reiterates that appId is the share code and stepId is the step's id, but adds no new syntax or formatting beyond what the schema provides. It reinforces the relationship but does not compensate for any gaps because there are none.

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 ('Expands') and a specific resource ('one step of an emit_app recipe'), and enumerates exactly what detail is returned (full instruction, why it matters, how to know it worked, what to do when it didn't). It also explicitly contrasts with the short form returned by emit_app, distinguishing it from the sibling tool.

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 clearly states when to use the tool: when a step needs more detail, because emit_app returns steps in short form. It also notes the prerequisite of needing the same share code and step id. It does not explicitly name 'use emit_app for the initial list', but the context is implied and clear enough.

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