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

Annotations already establish readOnlyHint=false, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the step carries its id and stats with it, and 'the steps around its old place close the gap' discloses the reordering side effect on other steps. It still omits constraints and failure modes for a mutation.

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?

A single dense sentence that front-loads the action and then the ordering consequence. Nothing is wasted, though the semicolon clause about gap closure could be slightly clearer as its own sentence.

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 2-parameter mutation with no output schema, the description covers the core effect and side effect but leaves out prerequisites, scope (must the step belong to the same campaign?) and the shape of the result. Adequate but with clear 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 coverage is 50%: insert_after is well documented in-schema with an explanation of start/step/branch targeting, while step_id is bare. The description only hints at step_id ('with its id') and adds nothing about insert_after semantics, so it neither compensates for the gap nor meaningfully extends what the schema already says.

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 names a specific verb and resource ('Move an email ... to another point in the campaign'), which is clearly distinct from add/update/delete_campaign_step siblings in the toolset. It does not explicitly name those alternatives, but the repositioning semantics are unmistakable.

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?

Usage is implied rather than stated: an agent can infer this is for relocating an existing step rather than creating or editing one. There is no explicit when-to-use/when-not guidance, no mention of prerequisites (e.g. whether the campaign must be a draft or whether the step must exist), and no sibling is named.

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