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

Annotations only indicate readOnlyHint=false, idempotentHint=true, and destructiveHint=false. The description goes far beyond by disclosing that the operation replaces the entire selection, fails closed on empty lists, re-verifies ids against live connections, and rejects unreachable ids. This is critical behavioral context that annotations alone do not provide, and it aligns with (and extends) the annotation hints.

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 long but packed with high-value information, front-loaded with purpose and then covering usage, behavior, and safety. Every sentence earns its place; the provider list repeats the schema but is harmless. It is well-structured and scannable, though it could be slightly trimmed without losing meaning.

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 configuration tool that mutates state across many providers, the description covers all essential aspects: what it sets, how to get ids, replacement behavior, failure modes, safety warning, and the complete provider list. It references the related list tool and gives clear operational guidance. Given no output schema, return details are minor. An agent can call this correctly with the provided information alone.

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 parameters are already described. The description adds practical meaning by specifying the accountIds source ('from list_connector_accounts') and clarifying that an empty array shares nothing, which is not fully evident from the schema. It reinforces provider choices by repeating the enum list, though this is slightly redundant. Overall, it enhances schema semantics without being essential.

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 opens with a specific verb and resource: 'Set WHICH of a connector's accounts this brand is allowed to post to and spend from.' It then lists concrete account types (Facebook Pages, Instagram, Google Ads, etc.) and explicitly contrasts with the sibling list_connector_accounts by instructing to pass ids from that tool. This makes the tool's purpose unmistakable and clearly distinguishes it from related list/disconnect tools.

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 provides explicit usage directives: 'Pass ids from list_connector_accounts,' explains the replacement semantics ('this REPLACES the current selection'), warns about empty list behavior, and advises consulting the user because 'posting as the wrong Page is a public mistake.' It also enumerates all providers, leaving no ambiguity about when to use this tool versus alternatives.

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