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

Goes well beyond the annotations (which only say non-readonly, non-destructive, non-idempotent) by disclosing the hard constraints an agent would otherwise trip over: 24 hours per day total, no future dating, 500-character note limit, and plan-gating that surfaces a plan-limit message. This is exactly the kind of precondition detail annotations cannot carry.

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?

Four short sentences, front-loaded with what the tool does before the constraints. No filler, and every clause carries a rule or scope fact.

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?

Complete for a small creation tool with full schema coverage: everything needed to call it successfully, including limits and plan requirements, is present. Minor gap is that it does not state what happens on success or how to correct a mistaken entry.

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 the baseline is 3; the description earns above that by adding validation semantics the schema lacks: the note length cap, the per-day hour ceiling, and the no-future-date rule, all of which constrain the 'minutes', 'note', and 'date' parameters.

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 (log) and resource (time on a task), plus the crucial scoping detail that it is the caller's own time rather than someone else's. That distinguishes it from sibling mutations like update_time_entry and delete_time_entry without needing to open a schema.

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?

Gives clear usage context: any team role, any task in the workspace, Pro plan only, with the consequence for Free workspaces spelled out. It stops short of naming the alternative tools (update_time_entry / delete_time_entry) for correcting or removing an existing entry, so the agent must infer that this tool only creates.

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