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

Annotations already establish this is a safe read (readOnlyHint true, destructiveHint false, openWorldHint false), so the bar is lower; the description still adds real behavioral context: an empty countries list is not evidence no audience is attached, and targeting.resolved false means the geographic scope could not be fully read. It does not mention auth needs, rate limits, or pagination behavior.

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 purpose and the return contents are front-loaded, followed by the important caveats. "These are the locations the campaign is configured to target" is slightly redundant with the opening sentence, but the rest of the text is dense and each caveat earns its place.

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?

With no output schema, the description carries the burden of explaining return values, and it does name the main fields and their meaning. For a simple read tool with full annotation and schema coverage, the main remaining gap is the shape/format of channel details and how multiple campaigns are keyed in the response.

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%, so all three parameters (including the omit-to-scan-account behavior of campaign_ids and the 25/100 bounds on max_campaigns) are already documented in the schema. The description adds no additional parameter semantics beyond that, so 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 ("Read") and resource ("configured geographic targeting of a campaign") and enumerates what is returned: targeting locations, channel details, and for native targeting audienceIds, targetGroupIds and resolvedFrom. It explicitly distinguishes itself from demographic_country_stats, which reports delivery rather than configuration.

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 context for use (reading a campaign's configured geo targeting) and names the alternative for a different question (demographic_country_stats for where delivery occurred, which "can differ from targeting"). It stops short of saying when not to use it or routing to siblings like set_search_channel_locations or get_campaign_by_wizard_id.

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