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

Annotations already cover readOnly/idempotent/non-destructive, so the bar is lower, and the description still adds real context: the required logins:read scope, the fact that every call is audited, and the warning-by-implication that a plaintext password is exposed. It does not cover failure behavior (e.g., login not found) or any rate limits.

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, zero filler, with the payload (what is returned) front-loaded before the auth and audit notes. Appropriately sized for a simple two-parameter read.

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?

A simple read tool with full schema coverage, complete annotations, and an output schema that carries return-value detail. The description adds the permission and audit context an agent needs and omits nothing essential.

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 100%, so both parameters (login id/exact name, project slug/id) are already documented in the schema. The description adds no additional syntax, format, or lookup nuance beyond what the schema provides, making the baseline 3 correct.

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 ('Reveal') and resource ('one saved login') and enumerates exactly what is returned (URL, username, password, notes). The word 'one' implicitly contrasts with list_logins, though the sibling is never named explicitly.

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?

Usage is implied: fetching a single login by id or exact name, as reinforced by the 'Requires logins:read' prerequisite. There is no explicit when-to-use vs. when-not guidance (e.g., use list_logins to discover ids first, or use update_login to modify).

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