fcrm update contact

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

Goes well beyond the annotations (destructiveHint=true, idempotentHint=false, openWorldHint=true) by disclosing that the operation is policy-enforced (SubscriberPolicy::verifyRequest), requires explicit local confirmation, may trigger hooks/announcements/automations affecting other people, and must not be retried. That is exactly the kind of side-effect and safety context structured fields 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?

Purpose is front-loaded and the capability/confirmation block is broken out cleanly. It is mildly cluttered by internal jargon (_Enforced by `SubscriberPolicy::verifyRequest()`_) that an agent doesn't need to invoke the tool, but overall the structure is efficient.

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 destructive, nested-object mutation with a strong annotation set, the description covers the essential gaps: capability requirement, confirmation expectation, side effects, and no-retry warning. No output schema exists, but a successful update's return is not what gates correct invocation. Minor shortfall is the absence of any note on partial-update semantics for the nested payload.

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 83%, so the schema already documents the key parameters. The line about the subscriber object or individual top-level fields mirrors the $defs description ("Contact data can be nested inside a `subscriber` object or passed at the top level"), so it adds little new semantic value. Baseline 3 applies.

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: "Update an existing contact's fields, custom values, tags, and lists." The update verb inherently separates it from fcrm_create_contact, fcrm_get_contact, fcrm_list_contacts, and fcrm_search_contacts. However, no sibling is named explicitly, so this falls short of the top band.

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?

It gives operational conditions (required capability, explicit local confirmation, no retries) rather than a when-to-use-this-vs-alternatives rule. The agent can infer that this is the mutation route for contacts, but nothing tells it when to prefer this over, say, fcrm_add_contact_note or fcrm_create_contact. Usage is implied, not spelled out.

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