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

The description discloses key behavioral traits: the fetch happens immediately (bounded by a few seconds), returns 'storiesAdded' immediately, may return 'fetched:false' if still fetching, and doubles as manual import or recurring search. This adds significant context beyond the annotations, which already indicate readOnlyHint=false and openWorldHint=true. The description does not mention rate limits or other side effects, but the openWorldHint covers unknowns.

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?

The description is two sentences long, covering purpose, behavior, and usage patterns. It is efficient but the first sentence is quite dense, mixing behavior and return values. Could be slightly restructured for clarity, but overall it's concise and front-loads the key action.

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?

Given the tool's complexity (4 parameters, two distinct use cases) and the presence of an output schema (reducing need to document return types), the description is complete. It explains the fetching behavior, the different modes (manual vs search), and ties to the next step (generate_content). No gaps remain.

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?

The description adds meaning beyond the input schema. It explains that 'value' can be a URL or search terms, and 'type' determines the source kind or search type. The schema only describes 'type' but not 'value' or 'projectId'. The description compensates for the low schema coverage (25%) by clearly explaining both parameters' roles. 'name' is optional and not covered, but it's self-explanatory.

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 clearly states the tool adds a source to a project and fetches it immediately. It distinguishes between manual URL import and recurring keyword search, which are distinct use cases. The verb 'adds' and resource 'source' are specific, and the description differentiates from siblings like 'remove_source' or 'list_sources' by detailing the fetching behavior and return values.

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 explains when to use the tool: to add a source for immediate fetching so that 'generate_content' can use it. It provides guidance on how to use it for both manual import and search creation. However, it does not explicitly state when not to use it or compare to other tools like 'betterpost_add_story' or 'betterpost_suggest_topics'.

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