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

Annotations only declare the write/non-idempotent/open-world profile; the description adds genuinely useful behavioral context the annotations lack - the one-time token returned by the upload step, the required second call after the file reaches storage, and the constraint that PDFs become documents attachable to LinkedIn posts only. Missing details like token expiry or size limits keep it from a 5.

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?

Front-loaded with the core action, then the mode-specific rules, then related tools - three tight sentences with no filler. Dense but every clause carries information; only slight comma-heavy phrasing costs a point.

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 10-parameter mutation with an output schema (so return values need no explanation), the description covers the required two-step flow, mode selection, and the PDF restriction. Remaining gaps (auth requirements, size/type limits, token lifetime) are minor.

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 coverage is 100%, so the baseline is 3, but the description goes beyond the field-by-field schema text by explaining cross-parameter sequencing: which fields go together for each source value and that blobUrl/mime/size are supplied on the second call. This adds conditional logic the schema does not express.

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 and resource ('Adds an image, video or PDF to the library') and immediately distinguishes the two operational modes (public URL import vs. upload start). An agent can tell what this tool does without opening the schema, and it names search_assets and save_post as related siblings.

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?

Explicitly says which parameters apply to which mode ('For a public https URL, pass source url plus url'; 'For a local file, pass source upload...'), including the two-phase upload sequence. It does not, however, state when to prefer this over update_asset or search_assets, so routing against siblings remains partly inferential.

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