direct_get_bid_modifiers

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so 'Read-only' is largely redundant. The description does add useful domain context by naming the supported levels (CAMPAIGN, AD_GROUP) and the kinds of adjustments, but says nothing about pagination behavior or the default limit of 1000 that govern result size.

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 with the resource and key constraint front-loaded and no padding. The ellipsis in '(mobile, demographics, retargeting, regional...)' is slightly loose but keeps it compact.

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 no explanation, and the description identifies the entities and levels. It still omits pagination/default-limit guidance for a tool exposing limit and offset, leaving a minor gap for correct invocation.

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 0%, so the description must carry the burden, and it partially does: 'levels CAMPAIGN, AD_GROUP' documents the levels parameter values, and 'by campaign/group/id' maps to campaign_ids, ad_group_ids, and ids. However, limit and offset — the pagination controls — are never explained, leaving two parameters undocumented.

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 resource (bid adjustments) with concrete examples of adjustment types and the entities it operates on (campaign/group/id) plus the levels it supports. It is clearly a read operation, though it does not explicitly distinguish itself from the sibling direct_get_bids, which an agent could plausibly confuse it with.

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?

No indication of when to use this tool versus alternatives such as direct_get_bids, direct_get_campaign, or direct_get_statistics. The only usage signal is the trailing 'Read-only', which is a capability note rather than routing guidance.

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