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

Goes well beyond the read-only annotations by disclosing key-dependent scoping ('with your lp_ key your own uploaded refs are included; without it only curated packs are searched') and the critical non-mutating behavior that this tool never attaches references. These are behavioral traits the agent could not infer from readOnlyHint alone.

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?

Three dense sentences, front-loaded with the core capability before scoping and routing details. Nearly every clause is load-bearing, though the sentence structure is packed enough to require a careful read.

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 search tool with no output schema, the description covers scope, key-dependent behavior, the return ('candidate images/clips with preview urls'), the non-attach contract, and the correct next step. Nothing essential for correct invocation 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 coverage is 100%, so the baseline is 3, but the description adds meaning: it explains what 'pack' scopes to and gives concrete semantic query examples ('warm golden diner', 'neon night street'). The lp_ key note further clarifies how results vary, which the schema does not convey.

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 ('semantic search over your media-reference library AND shared curated moodboards'), making the dual scope explicit. An agent can distinguish it from list_reference_packs (lists moodboards) and generate_image (attaches refs) without opening a schema.

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 routes: use 'pack' to search inside one moodboard picked from list_reference_packs, and states the downstream flow — never attaches, discuss candidates, then pin chosen ids via referenceIds on generate_image. Both the alternative tool and the follow-on tool are named with their conditions.

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