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

Annotations already declare readOnlyHint=false, idempotentHint=true, and destructiveHint=false, covering the basic safety profile. The description adds a small amount beyond that by mentioning 'Create or update' (upsert behavior) and emphasizing the filter definition. It does not disclose side effects, whether existing filters are replaced or merged, or any permission requirements, but the annotation coverage lowers the burden.

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 description is one short, direct sentence with no filler. It front-loads the core action and resource. It earns its place, though it could carry a bit more useful context without becoming verbose.

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?

The schema richly documents parameters and the filter grammar, so an agent can construct valid inputs. However, the description alone leaves ambiguity around create-versus-update behavior, return values (no output schema), and whether calling with only audience_id has meaningful side effects. These are notable gaps, but not fatal given schema and annotation coverage.

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 the schema already documents every parameter including the nested filter structure and example. The description's phrase 'filter definition' maps to the filter parameter but provides no additional semantic detail beyond what the schema already offers. Baseline 3 is appropriate.

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 action and resource: "Create or update an audience with a filter definition." It clearly distinguishes this from sibling tools like list_audiences, get_audience, and delete_audience. However, the dual verb 'Create or update' is slightly ambiguous against the tool name 'update_audience', though it may intentionally signal upsert semantics.

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 guidance is given about when to use this tool versus alternatives, or whether it is preferred over get_audience/list_audiences for inspection tasks. It also does not state when an audience is created versus updated, despite saying 'Create or update.' The context must be inferred entirely from the tool name and schema.

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