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

Annotations already declare the safety profile (readOnly=false, idempotent=true, destructive=true, openWorld=false). The description adds valuable context beyond them: the authorization requirement (eligible approver roles/designation), a feature gate (timeTracking PRO+), and a state precondition (entry must be SUBMITTED). It stops short of explaining what happens on success or whether approval is reversible, but that is a meaningful supplement.

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, front-loaded with the action, followed by eligibility and feature gating. No filler; every sentence earns its place.

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 low-complexity single-parameter mutation with no output schema, the description covers the action, authorization, gating, and precondition well. The remaining gap is outcome/error behavior (e.g., what if the entry is not submitted), which annotations alone do not resolve.

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 0% for the single entryId parameter, so the schema itself adds no meaning. The description implies entryId refers to a submitted timesheet entry, giving marginal semantic context, but does not describe the ID's format or source, leaving the burden mostly unmet.

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 ('Approve a single SUBMITTED timesheet entry') with the entry state constraint front-loaded. It implicitly contrasts with the sibling approve_timesheet_week via 'single ... entry', but never names the alternative explicitly, so sibling differentiation is inferential rather than stated.

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 the caller eligibility conditions (OWNER/ADMIN/MANAGER in managers mode, or a designated approver in approvers mode), which is solid context. However, it gives no explicit when-to-use vs approve_timesheet_week or reject_timesheet_entry, and no when-not guidance, so usage routing is left to inference.

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