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

readOnlyHint=true already tells the agent this is a safe read, and an output schema exists, so the description's burden is light. It adds only the batch hint ("one or more"); it says nothing about behavior for unknown canonicals (partial results vs. error) or any cap on list size.

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?

One short, front-loaded sentence with zero filler. It is arguably over-compressed for a tool with an alternative-sibling choice to make, but nothing in it is wasted.

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?

With one fully documented parameter, an output schema, and a read-only annotation, the structured data carries most of the load. Still, an agent would benefit from knowing how this differs from the two PROJECT_LIST siblings and what happens when a canonical is not found.

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 coverage is 100% and the single parameter is self-documenting ("List of project canonicals to fetch"), so baseline 3 applies. The description's "one or more" reinforces that arrays of any length are accepted but adds no format or identifier-syntax detail beyond the schema.

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?

"Get one or more projects by canonical" states a specific verb (Get), resource (projects) and lookup key (canonical), and the plural framing signals batch retrieval rather than a single-record fetch. It does not explicitly contrast itself with siblings like CYCLOID_PROJECT_LIST or CYCLOID_PROJECT_LIST_ENV, so the agent must infer the distinction.

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?

There is no statement of when to choose this over CYCLOID_PROJECT_LIST (list all) or CYCLOID_PROJECT_LIST_ENV (env-scoped). The agent must guess that this is the lookup-by-identifier path based solely on the word "canonical".

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