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

Annotations already declare destructiveHint=true, readOnlyHint=false and openWorldHint=false, so the safety profile is covered. The description adds the meaningful failure constraint that the fallback/last branch cannot be deleted (and therefore that this call can fail), but says nothing about flow-state prerequisites or side effects.

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?

Two short sentences, zero filler, with the action front-loaded and the hard constraint immediately after. Nothing is padded or redundant.

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 destructive, no-output-schema tool the safety hint and the fallback restriction are present, and the schema supplies full parameter detail. However, it omits prerequisites (e.g., whether the flow must be unpublished) and what happens to branches indexed after the deleted one, leaving real gaps.

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% and each of the 4 parameters is documented in the schema, including the 0-based indexing and the approval prompt requirement. The description adds no parameter meaning beyond what the schema already carries, so the baseline 3 applies.

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 ('Delete a branch from a router step') plus a hard constraint, so the agent knows exactly what the tool acts on. It does not differentiate from siblings like ap_delete_step or ap_update_branch, which is the only gap.

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 sentence 'Cannot delete the fallback branch' is a constraint, not usage guidance. There is no statement of when to use this versus ap_update_branch or ap_delete_step, and any prerequisite discovery is only implied by the schema's pointer to ap_flow_structure.

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