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

With no annotations, the description carries the burden and does well: it discloses that the operation is read-only and free, and that contact details stay masked until the set is bought — a significant behavioral constraint an agent would otherwise not know. It omits error behavior for invalid/unknown contact ids.

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?

Three short sentences, front-loaded with what the card contains, then the masking caveat, then the prerequisite. No filler.

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?

No output schema exists, so the description usefully lists the card's fields and the masking rule. It could say more about what masked vs unmasked output looks like and failure modes, but it is sufficient to call correctly.

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 both `slug` and `contact_id` are already documented. The description only restates the id's provenance ('Contact ids come from `get_audience_set_contacts`'), adding no new syntax or format detail — baseline 3.

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?

Specific verb and resource: 'Full card of one contact in a marketplace set', and it enumerates the card's contents (person, company, buying signal, channels). This clearly distinguishes it from the sibling list tool get_audience_set_contacts.

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 description states the prerequisite that contact ids come from `get_audience_set_contacts`, which tells the agent how to reach this call. It does not explicitly say when to prefer this over other single-contact tools (e.g. sdr_get_person_detail) or when not to call it.

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