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

With no annotations present, the description carries the full behavioral burden and does so well: it discloses partial-update semantics, the manage-access requirement, the return value, and non-obvious domain rules about category precedence and the 'other' fallback bucket. This is exactly the context an agent cannot get from the schema.

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-loads the verb and resource, then layers semantics efficiently in four sentences. The middle sentence on transaction-to-line matching is somewhat expansive for an update tool but is justified because it explains how position and categoryIds actually behave.

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?

No output schema exists, and the description closes that gap by stating 'Returns the updated line.' It covers auth, mutation scope, and matching semantics. It does not describe the shape of the returned line object, a minor remaining gap.

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%, so all six parameters are already documented, including 'Earlier lines win when category sets overlap' and 'parents expand to their children'. The description restates the field list and matching rule without adding syntax or constraints beyond the schema, which matches the baseline 3 for high-coverage schemas.

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 (update) plus resource (tracker line) and enumerates exactly which fields are mutable: name, categories, limit, position. This cleanly separates it from create_tracker_line and delete_tracker_line, which share the same resource noun.

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?

Gives clear operational context: 'Only passed fields change' establishes patch semantics, and 'Requires manage access to the tracker' states a prerequisite. It does not explicitly name alternatives such as update_tracker or create_tracker_line, so it falls short of full when/when-not routing.

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