canvas_module_file_content

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

Annotations already declare readOnly, idempotent, non-destructive and open-world behavior, so the bar is lower; the description still adds real value by naming the public-sharing prerequisite and the external-link failure mode. It also discloses the ZIP-entry and offset continuation model. It does not describe truncation/next_offset behavior explicitly, which is the main remaining behavioral gap.

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 purpose is front-loaded in the first clause and the enumeration of supported sites is scoped appropriately. The cross-reference 'Same text options as canvas_file_content' is mildly wasteful since it pushes the reader to another tool's docs.

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 covers input preconditions, the read-only nature, and where to get IDs indirectly via the schema's 'from canvas_module_items'-style hints. With six parameters at full schema coverage, this is close to sufficient; only the pagination/truncation contract is left unstated.

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 the baseline is 3, and the description only restates the parameter names already documented in the schema ('offset, max_chars, entry for ZIPs'). It adds no format, default, or range detail beyond the schema, so it earns no credit above baseline.

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 verb ('Read the TEXT') against a precisely scoped resource (a module item that is either a Canvas File item or an ExternalUrl item) and enumerates the supported link targets. It distinguishes itself from named siblings (canvas_file_content, canvas_link_content, canvas_module_file) so an agent can route without opening schemas.

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 clear context plus explicit exclusions: 'For the original file itself use canvas_module_file' and 'Takes Canvas IDs only, never a URL.' It also states a prerequisite ('Google and Dropbox files must be shared publicly'). It stops short of telling the agent when this is preferred over canvas_file_content, only that they behave the same.

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