Log Tail

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering basic safety. The description adds useful behavioral context beyond annotations, such as 'fastest way' (performance) and specific parameter behaviors like skip_postrun and direct_log_url, which are not in the annotations.

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 compact, with a two-sentence opening that gets straight to the point, followed by a well-organized Args list. Every line adds value and there is no redundant filler.

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?

Given that an output schema exists, the description does not need to explain return values. It covers the core purpose, provides alternatives, explains parameter behaviors, and includes defaults, making it sufficient for an agent to select and invoke the tool correctly.

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 input schema has no descriptions (coverage 0%), but the description's Args section thoroughly explains all 7 parameters, including defaults, maximums, and alternatives (uuid vs url, direct_log_url). This fully compensates for the schema gap and makes parameter usage clear.

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 with a specific verb and resource: 'Get the last N lines of a build log'. It also provides a use case ('fastest way to see why a build failed'), distinguishing it from siblings like get_build_log and stream_build_console.

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 compares to an alternative: 'More token-efficient than get_build_log(mode="summary") when you just need the tail.' This gives the agent clear conditions for when to choose this tool and when another might be better.

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