open_item

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

The description discloses important runtime behavior beyond the readOnlyHint/openWorldHint annotations: long PDFs return a page map and require a second call with pages, and max_chars limits file text. It also explains what each item type returns, which is substantial behavioral context.

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 description is well-structured: a one-line summary, scannable item-type bullets, and an Args section. Every sentence adds useful information, and the long-PDF behavior is front-loaded where it matters most.

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?

For a read-only opener with seven item types and three parameters, the description covers all relevant behaviors and return shapes. An output schema exists, so detailed return fields need not be repeated. No critical calling context is missing.

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 0%, so the description must carry parameter meaning. It fully does: item_id is sourced from specific tool outputs, pages includes concrete format examples like '1-5' and '2,4,10-12', and max_chars is tied to truncation and page-map behavior.

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 and resource: 'Open any course item by id and return its content.' The item-type bullets further clarify what each kind of item yields, and references to read_file/read_discussion distinguish it from those sibling tools.

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?

It states where item_id comes from (course_overview, search, upcoming_deadlines) and gives explicit alternatives for drilling into specific items, e.g., 'read one with read_discussion' and 'read one with read_file.' This gives an agent clear routing guidance.

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