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

Annotations already declare destructiveHint=true, idempotentHint=false, and openWorldHint=true, so the safety profile is covered. The description does add one genuinely useful non-annotation fact — the master API key requirement — but says nothing about what is overwritten, whether partial updates are possible, or the semantics of async processing beyond what the schema states.

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 authored content is two short, front-loaded sentences with no filler. The injected aisa-pricing block adds length but is machine-appended boilerplate rather than authorial verbosity, so it is only a minor deduction.

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?

An output schema exists, so return values need not be described, and annotations cover the destructive/idempotency profile. What is missing for a nested-object mutation is the two-mode usage model and any guidance on selecting between uniform and per-account updates, which an agent cannot infer from the wrapper schema alone.

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 reported at 0% for the single top-level 'body' parameter, so the description carries the burden and does not meet it. It never explains the critical account_ids vs account_attributes duality, the async constraint, or the per-account versus uniform-update distinction that determines how the call must be shaped.

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+resource (bulk update accounts) and the 'bulk' qualifier correctly scopes it against the single-record sibling patch_apollo_accounts_account_id. It does not, however, explicitly name or distinguish itself from post_apollo_accounts_bulk_create, post_apollo_accounts_update_owners, or post_apollo_contacts_bulk_update, which share the same bulk-mutation pattern.

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 only guidance is 'Requires a master API key.' There is no statement of when to use this versus the single-record PATCH, the bulk_create, or the update_owners/update_stages variants, and no mention that two mutually exclusive update modes exist inside the body.

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