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

With annotations already declaring non-read-only, non-idempotent, and non-destructive behavior, the description adds useful behavioral context: the uniqueness-conflict failure mode and the important limitation that member resources are not moved. It does not discuss permissions or reversibility beyond what annotations imply.

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?

Three tightly written sentences with no waste. The core action and identifier definition are front-loaded, followed by the failure condition and the scope caveat.

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 mutation tool with an output schema and informative annotations, the description covers the key operational facts an agent needs: what is renamed, what causes failure, and what is not affected. Minor gaps around permissions or tenant-level side effects remain, but they are not critical here.

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 both parameters are already fully documented, including the uniqueness constraint and hierarchical path segments for new_slug. The description reinforces the same concepts but does not add syntax or format details beyond the schema.

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 and resource ('Rename an app's slug') and immediately defines the slug as the app's unique per-tenant identifier and folder prefix. It also distinguishes this operation from broader app updates by clarifying that it does not move member resources.

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?

It provides a clear failure condition ('Fails if the new slug is already in use') and an explicit scope caveat that member resources are not moved. It does not name a sibling alternative such as update_app or rename_schedule_slug, so it stops short of full routing guidance.

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