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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is conveyed structurally. The description confirms the deletion targets custom (not global) feeds but adds nothing about irreversibility, side effects on scheduled posts, or failure modes for an invalid or global source ID.

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?

Two short sentences, zero filler, with the action stated first and the prerequisite follow-up second. Every clause earns its place.

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 one-parameter destructive tool with full schema coverage, no output schema, and annotations carrying the safety semantics, the definition covers what an agent needs to call it. A note on what happens to references after deletion would make it complete.

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% and the single parameter is documented as 'Unique ID of the custom source to delete.' The description reinforces the ID-based addressing and points to list_sources for retrieval, but adds no format or sourcing detail beyond the schema, so the baseline 3 applies.

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 specific verb and resource ('Delete a custom news feed') and the 'custom' qualifier implicitly separates it from global-source siblings such as disable_global_source, although none of those siblings are named outright.

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?

It supplies a concrete prerequisite path by directing the agent to list_sources to obtain a source ID, which is exactly the guidance needed before invoking. It does not state when deletion is inappropriate versus toggle_source or add_source, so it falls short of a full when/when-not treatment.

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