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

With no annotations, the description carries the full burden and does disclose key behaviors: the returned url is a stable public link, the tool is idempotent-by-path ('Re-uploading the same relative_path replaces the previous asset'), and both raw base64 and data-URL inputs are accepted. It omits permission requirements (present only in the schema) and rate/size limits, keeping it short of full coverage.

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?

Purpose is front-loaded in the first sentence, followed by return-value guidance and input/replacement notes. Four tight sentences with minimal waste, though the URL-usage sentence is slightly padded.

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 mutation tool with no annotations and no output schema, the description usefully explains the return value (stable public url and where it can be embedded) and the replacement semantics. Authorization and size limits live in the schema and keep it from being fully self-contained.

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. The description largely restates what the schema already says about content_base64 (raw base64 or data URL), adding no new syntax or constraint details beyond the structured fields.

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 ('Attach') and resource ('binary asset') against the target report, with concrete examples of asset kinds (image, video, font, CSS, JS). An agent can tell this is the upload counterpart to siblings like delete_report_asset and list_report_assets, though no sibling is named 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?

The description implies when the tool is used (to make a binary referenceable inside report HTML) but never states when to prefer it over alternatives or any exclusions. The re-upload clause gives operational context but not selection guidance.

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