add_line_to_repertoire

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

With no annotations, the description fully discloses side effects: it joins existing branches, never reorders variations (and explains why), schedules new positions automatically, leaves existing cards untouched, and backs up previous contents. It also warns about the app's silent overwrite risk, providing critical context.

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 dense paragraphs, each adding critical information: purpose, behavioral details, and prerequisites/backup. No wasted sentences; every sentence earns its place.

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?

Covers purpose, side effects, prerequisites, and data integrity guarantees. As a 2-parameter mutation tool with an output schema, it is sufficiently complete without needing to describe return values. The description details all important behavioral traits.

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 description clarifies that 'moves' are SAN moves from the starting position, adding meaning beyond the schema's bare 'array of strings'. However, 'name' is not explained (presumably the repertoire name), leaving that parameter ambiguous. With 0% schema coverage, description only partially compensates.

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 clearly states the verb ('Merge') and resource ('a line of SAN moves from the starting position into a repertoire'). It also differentiates from sibling tools by specifying the join behavior, making it the only write-oriented tool among lists/reads.

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 context is implied rather than explicit. No alternative tools are mentioned or when-not-to-use guidance provided. The prerequisite ('En Croissant must be closed') is given, but the description does not directly say 'use this when you want to add a line' or contrast with other operations.

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