Find a supporter

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

Annotations only declare readOnlyHint and openWorldHint; the description goes substantially beyond them by disclosing exactly which fields are returned by default, that email/phone/address/DOB require include_contact_details, that card and bank fields are never returned, and that contact-pattern redaction is applied unless contact details are requested. This is exactly the kind of non-obvious behavioral context an agent needs.

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?

Four sentences, none wasted: lookup key first, then default return set, then the gating flag, then the redaction caveat. Dense but front-loaded. Slightly long, and the return-value detail could be tightened, but every sentence carries information.

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 correctly carries the burden of explaining return values and field gating, and it does so thoroughly. The remaining gap is the absence of any statement about required inputs (0 required params) or error behavior when neither email nor supporter_id is provided.

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 baseline is 3, but the description adds real meaning the schema lacks: it explains the concrete effect of include_contact_details (unlocks email, phone, address, DOB, custom fields and disables redaction) rather than just restating the field list. include_questions and include_memberships are only echoed from the schema, keeping this short of a 5.

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 and resource ('look up one supporter') and names both lookup keys (email address or supporter ID). The 'one supporter' framing clearly distinguishes it from the sibling query_supporters without the agent needing to open 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?

Usage is implied by 'one supporter by email address or by supporter ID', which makes the single-record intent clear relative to the plural query_supporters. However, it never explicitly names the alternative or states when-not to use it, and with zero required parameters the description gives no guidance on what happens if neither key is supplied.

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