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

Annotations already declare readOnly, idempotent, and non-destructive behavior, so the safety profile is covered. The description adds real value beyond that: authorization tiers (guest/member/owner/admin/org key), handling of the private service credential, and an explicit data-disclosure boundary ('Mailbox passwords and message content are never returned'). The lack of any error/not-found behavior keeps it just short of a 5.

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?

Five short sentences, front-loaded with the core action before the access and data rules. Dense but each clause carries information. The 'private service credential stays on the server' line is tangentially relevant to the caller and slightly boilerplate, keeping it from a 5.

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 carries the burden of describing returns, and it does disclose the key negative case (no mailbox passwords or message content). For a simple two-param read tool with full annotation coverage, this is nearly complete; only the shape of a successful 'job' response and not-found behavior are unaddressed.

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% and both parameters carry inline descriptions, so the schema already does the heavy lifting. The description adds no syntax, format, or meaning beyond the schema for organization_id and resource_id, so the baseline of 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: 'Read one durable job in this organization'. The scope (single job, current organization) is clear, and it is distinguishable from write-oriented siblings like mailbox_create or domain_create. However, it does not define what a 'job' is or contrast itself with other read siblings such as organization_get or domain_get.

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?

Provides access-condition guidance ('No guest access. Members can read. Owners, admins and organization keys can manage email'), which tells the agent who is allowed to call it. It does not state when to use this tool versus alternatives or what prerequisites (e.g. a valid job/resource_id) are needed, so usage is only implied.

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