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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world scope, so the safety profile is fully covered without the description. The description does add useful behavioral content by stating the note includes a plain-text body and an audio url, telling the agent this is a full-content fetch rather than a metadata lookup, but much of that overlaps the existing output 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?

Two tight sentences, with the identifying operation and returned fields front-loaded before the caveat. The disclaimer sentence is short and plausibly earns its place as domain-safety context, though it is not strictly about invocation.

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?

An output schema exists and annotations are rich, so the description need not explain return structure or safety; it correctly spends its words on identifying the record and signalling full-body content. The only real gap is the absence of guidance on obtaining a valid slug or choosing this over sibling content tools.

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?

Only one parameter, and the input schema documents it at 100% coverage including the example "xpub-is-not-a-public-key" and its provenance ("Note slug from list_notes"). The description's "by slug" adds no format or lookup detail beyond the schema, 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?

"Get one note by slug" gives a specific verb and resource, and the following enumeration of fields (title, description, publishedAt, tags, url, audio url, sources, plain-text body) makes clear exactly what a note record contains. It implicitly contrasts with list_notes by specifying a single note keyed by slug, though it never names that sibling explicitly.

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 when-to-use guidance at all — nothing says to call this after list_notes or search_content surfaces a slug, nor how it differs from get_guide, get_pillar, or get_listing. The only qualifying sentence, "Education only, not financial advice," is a domain disclaimer rather than routing guidance.

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