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

Annotations already declare idempotency and non-destructiveness, yet the description adds genuinely new context: it spends one monitor (a quota cost not visible in annotations) and clarifies what idempotency means in practice ('same plan id returns the first result'). It also describes the return payload. It stops short of covering permissions or failure modes, so not a 5.

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?

Four tight sentences, front-loaded with the usage trigger, then return value, cost, idempotency, and the sibling exclusion. Every sentence carries distinct information with no repetition.

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 compensates by stating what is returned (the dependency with id and watch method). It also covers cost and repeat-safety, so an agent has everything needed to call it correctly and set expectations.

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 both parameters are already documented (including the instruction to show the confirm sentence to the user). The description reinforces that plan_id drives idempotency but adds no new syntax or format detail beyond the schema. 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?

States a specific action on a specific resource (add the dependency from a confirmed plan_dependency plan) and explicitly separates it from the sibling plan_dependency (planning) and create_site (site-embedded dependencies). An agent can identify the correct tool without opening the schema.

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 an explicit precondition (user confirmed the plan), an explicit exclusion ('Not for a dependency inside a plan_site plan: create_site adds those with the site'), and names the alternative. When-to-use and when-not-to-use are both covered.

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