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

Annotations only say readOnlyHint=false and destructiveHint=false, so the description carries the behavioral burden—and it delivers richly. It discloses the 200-item per-call limit, the upsert semantics ('Existing companies are updated, not duplicated'), the domain-resolvability requirement, and the failure-handling behavior ('reported back as failed rather than silently dropped'). These are exactly the non-obvious behaviors an agent needs to predict side effects.

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?

Four tightly packed sentences, each earning its place: purpose, usage condition, capacity/row requirements, then update and failure semantics. The core purpose is front-loaded in the first sentence, and there is zero filler or repetition of schema content.

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 bulk write tool with no output schema, the description covers purpose, usage triggers, size limits, row validation, dedup behavior, and error reporting. The only gap is the response shape—it notes failures are 'reported back' but never specifies the return payload. This is a minor omission given the richness already present.

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 descriptions cover 100% of parameters, so the baseline is 3. The description adds genuine value beyond the schema: the 'Up to 200 per call' cap on the companies array is not in the schema, and it reinforces the domain-or-website requirement that maps to the 'domain required unless website is given' constraint. It does not document each field, but the schema already does.

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 ('Push'), resource ('companies into Xmagnet'), and scope ('MULTIPLE... in one call'), and explicitly names its sibling counterpart ('the bulk version of create_company'). An agent can immediately distinguish this from create_company, create_contact, and upload_contacts without opening the 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?

Gives an explicit when-to-use condition: 'Use when the user pastes or produces a list of companies to save to Xmagnet.' It also references the alternative tool (create_company) via 'the bulk version of.' However, it stops short of explicitly stating the when-not case (e.g., for a single company, use create_company), so exclusions are implied rather than stated.

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