lastscanned — 542-Carrier Package Tracking, Webhooks & Watches

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

readOnlyHint=true already establishes the safety profile, so the description only needs to add return-content context; saying it yields 'carrier ids' does that minimally. It says nothing about whether the list is static or account-scoped, or the id format, which would be the genuinely additive details.

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?

One short fragment with no waste, but it is under-specified rather than concise — a single complete sentence stating that it returns the set of valid carrier ids would cost no more space and be clearer.

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?

With no output schema, the description carries the burden of explaining the return value; 'carrier ids' is a start but leaves format (array of strings?), stability, and scope unstated. For a trivial no-param lookup this is adequate but not 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?

The tool takes zero parameters, so the schema-coverage baseline is a 4. The description does add cross-tool value by naming the 'carrier' parameter these ids feed into, which the schema alone cannot 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?

The description is a noun phrase, 'Carrier ids that can be passed as carrier,' which conveys the resource (carrier ids) but not an explicit verb or what the call actually returns. It does implicitly separate this from track_package/track_packages as a reference lookup rather than a tracking action.

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 clause 'that can be passed as carrier' hints at the use case — populating the carrier parameter on the tracking tools — but never states when to call this versus just calling track_package directly, nor any prerequisites.

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

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered; the description contributes value by disclosing the return payload (status, ETA, full scan history) in the absence of an output schema. It does not mention latency, per-carrier rate limits, or failure behavior for unknown numbers.

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 15-word sentence with the return content front-loaded and zero filler. It is a noun phrase without an action verb, but nothing is redundant or buried.

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?

Covering the three return categories compensates somewhat for the missing output schema, and the schema handles parameters fully. However, for an open-world external-call tool with a clear sibling, the absence of any guidance on track_packages vs track_package, or on invalid/unknown tracking numbers, leaves real gaps.

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 schema itself explains both parameters, including the carrier auto-detection behavior and the list_carriers pointer. The description adds no parameter meaning beyond that, so 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?

Names a specific resource (one tracking number) and enumerates exactly what is returned: current status, estimated delivery and scan history. Clear enough to select without opening the schema, though it never contrasts with the sibling track_packages (bulk), leaving single-vs-many as an inference from the name.

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?

No explicit when/when-not statement or named alternative. The phrase 'one tracking number' implicitly signals the per-package counterpart to track_packages, and the carrier parameter points at list_carriers, but neither is stated in the description itself.

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

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

Adds real behavior beyond the readOnlyHint/openWorldHint annotations: partial-failure isolation ("one bad number never fails the rest") and a per-carrier cap of 35 that is not expressed in the schema's maxItems of 100. It doesn't cover ordering of results or what fields a per-entry "result" contains.

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 batch-size constraint front-loaded before the error-handling guarantee.

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 two-parameter read-only tool with no output schema, this covers the constraints and failure semantics an agent needs to call it correctly. Only the shape of a successful per-entry result and result ordering are left unstated, which is minor.

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?

At 50% schema coverage, the description compensates by explaining the tracking_numbers array: batch size and the 35-per-carrier constraint that the schema omits. The carrier parameter's meaning (auto-detect when omitted) is already carried by the schema, so nothing critical is missing.

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 ("Track ... numbers") plus the defining scope of the tool: batch, up to 100 numbers with 35 per carrier. This distinguishes it from the singular sibling track_package by implication, though it never names the sibling explicitly.

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 batch limits (100 total, 35 per carrier) imply this is the bulk path and track_package is the single-item path, but the description never says so. There is no explicit when-to-use/when-not or pointer to a sibling, leaving routing to inference.

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