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

Annotations already declare the write/non-idempotent/non-destructive profile, so the description's job is to add context — and it does: the defaults applied when fields are omitted (domain, cost model, rotation) and the fact that the response includes click_url. It does not mention permission requirements or what happens on alias collision beyond the schema note, leaving a small gap.

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?

Four tight sentences, front-loaded with the core action, then defaults, then the two build paths, then the return value. Dense but every clause carries information; no filler or repetition.

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 34-parameter tool with no output schema, the description covers the essentials: required minimum, defaulted behavior, the shortcut-vs-full-tree decision, and the return value (campaign with click_url). It leans on get_campaign for the flows shape rather than restating it, which is appropriate, though a pointer to get_campaign_preflight-style validation or alias uniqueness handling is absent.

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 79%, so the schema already carries most parameter meaning; the description adds value by stating only name is required, naming the three defaults, and pointing to get_campaign include=flows for the flows tree shape. That is real added meaning but it does not fill the remaining ~21% of undocumented parameters, so it sits at the baseline rather than above it.

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?

Opens with a specific verb+resource: 'Create a manual tracker campaign.' The word 'manual' implicitly separates it from create_campaign_from_meta and clone_campaign, but no sibling is named explicitly, so the distinction relies on the agent inferring it.

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?

Gives clear routing between the two creation modes: the offer_id/landing_id shortcut for a single destination versus sending a full flows tree, and notes offer_id is ignored when flows is sent. It does not say when to prefer clone_campaign or create_campaign_from_meta over this tool, so sibling-level guidance is missing.

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