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

Annotations only say readOnlyHint=true; the description adds far more: the meaning of a false capability flag and the reconnect remediation, the derivation rule for `belongs_to`, the null=unfiled and プライベート edge cases, and that labels with zero accounts still appear in belongs_to_options. That is substantial context an agent could not obtain from the annotations.

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-loaded with purpose and the capability enumeration before the operational caveats. It is dense but each part carries information; the only soft cost is the long inline parenthetical tool lists (drive_content, contacts family) that read as clutter in a single wall-of-text paragraph.

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?

There is no output schema, so the description carries the return contract — per-account fields (account, connector, connector_label, belongs_to, readable, sendable, Google-specific booleans) plus belongs_to_options. For a zero-param discovery tool this is complete enough to call correctly and interpret 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?

Zero parameters, so the schema baseline is 4. The description goes beyond that by defining the semantics of the returned values (capability booleans, belongs_to derivation, belongs_to_options as the only valid add_memory input), which does real work for downstream calls.

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?

Opens with a specific verb and resource — an inventory of connected accounts and workspaces — and enumerates the exact connectors covered (Google/Gmail, Slack, Facebook Messenger, Chatwork). It is impossible to confuse with siblings like list_labels or list_calendars because the scope is organization-level account discovery, not per-connector content.

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?

Explicitly states when to call it ('call it FIRST to learn valid labels and how many Gmail accounts exist before sending'), when not to rely on alternatives ('don't guess from search results'), and routes to sibling tool families for Chatwork ('send_message does not handle Chatwork'). It even names the user questions it answers, which is unusually concrete routing guidance.

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