update_metric_direction

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

With no annotations, the description must carry the full behavioral burden. It does disclose a real behavioral consequence – the value steers optimizer search and best-trial ranking – which is useful. However, it says nothing about permissions, whether the value can be changed repeatedly, or any side effects on already-recorded trials, so the mutation profile remains partly opaque.

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?

Front-loaded with the action and resource, then the enum semantics, then the rationale – a sensible ordering with no filler sentences. It loses a point because the 'minimize/maximize' explanation largely duplicates the schema's parameter description, so that block does not fully earn its space.

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 2-parameter mutation tool with an output schema, the description covers purpose, value semantics, and rationale sufficiently. The only material gap is the absence of any auth/permission or reversibility note, which matters more given there are no annotations to supply it.

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% and both parameters are already documented, including the enum meanings for metric_direction. The description restates that same 'minimize = loss-like / maximize = quality' mapping rather than adding new format, default, or constraint information, 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?

The first sentence states a specific verb (Update) and a specific resource/field (optimization direction for an existing programme), so it is immediately distinguishable from create_programme and the other programme-management siblings. Nothing about the intent is ambiguous.

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 closing sentence gives an explicit when-to-use condition – programmes created before metric_direction existed on create_programme – which both routes the agent away from the sibling and explains the migration scenario. It also implicitly frames the normal path (set direction at creation) rather than calling this tool.

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