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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds real behavioral value beyond this: the response contents (including the negative_space semantic 'what does NOT belong in the folder'), the include_tree expansion behavior (ancestor chain and children), and the root:true special-case behavior. It omits error behavior (e.g., what happens when id does not exist), but with annotations carrying the safety burden, the added context is strong.

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 core action is front-loaded in the first sentence, followed by response contents, then optional parameters, then the root-container caveat. The root:true warning earns its place — it prevents an agent from wasting a call on containers-update. The paragraph is dense but every clause carries information; it is slightly long but justified by the semantic richness.

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 no output schema, the description compensates by enumerating the key return fields, covering the special root case, and providing sibling routing. For a read-only single-get tool with only two parameters, this is largely complete. It does not mention error handling for nonexistent IDs or permission requirements, but these are minor against the readOnlyHint=true and idempotentHint=true annotations.

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 id and include_tree are already documented in the schema. The description restates 'Required: id (integer)' and explains include_tree as 'also get ancestor chain and children,' which largely mirrors the schema's 'Include ancestors and children arrays (default: false).' The negative_space clarification concerns the response object rather than parameters, so the description adds only marginal value 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?

The description opens with a specific verb+resource+scope: "Get a single container by ID," and enumerates the exact fields returned (notes_count, children_count, description, negative_space, LLM instructions), which distinguishes it from the sibling containers-list tool that retrieves collections. It also clarifies the notable root: true special case, sharpening exactly what entity this tool targets.

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?

The single-by-ID phrasing implicitly separates it from containers-list, and it explicitly names containers-update as the tool that refuses root containers, routing the agent to instructions-update for that edge case. It does not explicitly state 'use containers-list instead when you need multiple containers,' leaving that primary alternative unspoken, but the routing guidance it does give is precise and actionable.

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