Find Subscriber by Custom Field

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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds that it 'returns matching subscribers' but does not disclose matching semantics such as exact vs. partial matching or result limits, which would add useful behavioral context.

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 two short, direct sentences with no filler. It front-loads the purpose and immediately states the expected result.

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 simple two-parameter read-only lookup, the description plus fully documented schema and readOnlyHint is mostly sufficient. It states that matching subscribers are returned, though it does not specify response shape or pagination; these are minor gaps given the tool's simplicity.

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%, with both field_name and field_value already documented. The description adds no further meaning about parameter behavior, so the baseline score of 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 states a specific action ('search') on a specific resource ('subscribers') and the distinguishing criterion ('custom field value'). This clearly separates it from sibling tools like manychat_find_subscriber or manychat_get_subscriber.

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 usage context is implied: use this when you need to find subscribers by a custom field value. However, it does not explicitly state when not to use it or name alternatives such as manychat_find_subscriber.

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