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

Annotations declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the agent knows this is a non-idempotent mutation. The description adds nothing beyond that: it says nothing about partial-vs-full update semantics (critical with 23 nested params), whether omitted fields are preserved or cleared, credential re-supply requirements, or auth scope.

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?

A single efficient sentence with no padding, but the phrasing ('update image source that has previously been created') is slightly awkward and front-loads no essential constraint such as required ID or update semantics.

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 23-parameter mutation with deeply nested conditional backend objects and an output schema, the description is far too thin. It omits update semantics, conditional field requirements, and any behavioral caveats an agent needs before invoking it.

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 78%, so the schema largely documents parameters itself, and the description adds no additional parameter meaning. The baseline of 3 for high coverage applies; the description does not explain the conditional storage-backend objects keyed off 'type'.

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 states a clear verb+resource: 'update image source'. It does not, however, differentiate this tool from its many siblings (create_image_source, delete_source, get_image_sources_source_id), so an agent must infer the distinction from the name alone.

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?

There is no guidance on when to use this over create_image_source or get_image_sources_source_id, no prerequisites (e.g., an existing valid image_source_id), and no mention that the resource must already exist beyond the vague 'previously been created'.

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