start_execution

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

With no annotations provided, the description carries the full burden and delivers: it discloses that the tool 'Records the start timestamp for duration tracking' and that 'The execution status changes to running.' These are the key behavioral effects. It could add edge-case behavior (e.g., idempotency), but the core behavior is transparently described.

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?

The description is three short sentences that front-load the main action, then add the prerequisite and effects. Every sentence earns its place with no fluff or redundancy. Very efficient.

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?

This simple tool has no parameters, an output schema exists (so return values are already defined), and the description covers purpose, timing, and state change. It lacks an explicit mention of what happens if no active execution exists, but overall it is complete for its complexity.

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?

The tool has zero parameters, so schema coverage is 100% vacuously. Description correctly adds no parameter information since none exists. Baseline for 0 params is 4, and there is no gap to compensate for.

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?

The description clearly states the tool's function: 'Start timing the active execution.' It specifies the resource (execution) and the action (start timing), and references a related tool (create_execution) to provide context. It distinguishes itself from siblings like stop_execution by defining its role in the execution lifecycle.

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?

The description explicitly instructs 'Call after create_execution()', providing a clear usage context. It implies a sequence without naming alternatives or exclusions, which fits the 'clear context, no exclusions' level. For a simple tool, this is sufficient guidance.

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