create_time_entry

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

No annotations are provided, so the description carries the full burden. It discloses one behavior (omitting `end` starts a live timer), but that same fact is already in the schema's `end` property description, and nothing is said about timer conflicts, required permissions, reversibility, or side effects on siblings like get_current_timer/stop_timer.

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?

Two short sentences with zero filler, and the core action is front-loaded ahead of the behavioral nuance. Nothing needs trimming and nothing is padded.

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 7-parameter mutation tool with no annotations and no output schema, the description is thin: an agent can call it correctly thanks to full schema coverage, but gets no signal about interaction with an existing live timer or the return shape. Adequate, with visible gaps.

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% – all 7 parameters (start, end, tagIds, taskId, billable, projectId, description) are documented in the schema itself. The description adds no format, constraint, or relationship detail beyond the schema's own 'Omit to start a live timer' note, so the baseline 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+resource ('Create a time entry') and adds a second capability ('start a live timer' when `end` is omitted). This clearly separates it from update_time_entry, delete_time_entry and stop_timer, though it never names those siblings 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 only implied: an agent can infer this is the creation path versus update/delete/stop siblings, and the 'omit `end`' clause gives one real branching rule. There is no explicit when-to-use guidance, no prerequisites, and no mention of what to do if a timer is already running.

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