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

Annotations only declare readOnly/openWorld/non-destructive; the description adds substantive behavior beyond them — alphabetical ordering, that only active customers return unless include_inactive is true, 100-item page size with cursor pagination, and the Cotlet API key/auth requirement. These are exactly the traits an agent needs that annotations cannot express.

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?

Front-loads the purpose ('Customer cards with...'), then layers filtering, ordering, downstream usage, pagination and auth in a logical order. Every sentence earns its place, though the single dense block could be tightened slightly.

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 still explains the returned shape (cards with ID, name, email, terms), ordering, pagination mechanics, filtering semantics and auth needs. An agent has everything required to call it correctly and consume the result.

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 coverage is 100%, so baseline is 3, and the description goes beyond the schema by explaining that search matches name, card ID OR email and that inactive records are excluded by default. The pagination and search semantics add usable meaning, though limit/cursor behavior largely mirrors the schema.

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 (list) and resource (customer cards), enumerates the returned fields (card ID, name, email, payment terms), and describes filtering, ordering and scope. An agent can distinguish it from sibling MYOB tools like get_invoice without opening the schema.

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 downstream context: 'Use customer_id from each item in create_invoice, record_invoice_payment and send_customer_statement,' which tells the agent why and when to call it. It stops short of naming an alternative tool or explicit exclusions, but for a list-by-filter tool the guidance is solid.

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