Centering Lab

Card centering standards and sources

get_centering_standards

Read-onlyIdempotent

USE ONLY for questions about published THRESHOLDS, tolerance, rules or SOURCES without grading the user's supplied numeric ratios. For PSA 10 compatibility with supplied ratios use grade_centering instead; it applies rounding and house-specific rules. If face/axis is unknown, ask first without any call. Example: {"house":"BGS","face":"back"}; fields optional, {} returns all. Houses PSA/BGS/CGC/SGC (case accepted), TAG excluded: explain proprietary assessment; never substitute another house. Face front/back in English; case/spaces accepted, reverse/obverse and translations rejected. SGC back has empty bands, no published table or ceiling; never invent one. Returns official/interpreted/approximate status, sources and verification. Not a final-grade prediction.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`face`	No	Face: front or back, in English. Ask the user if unknown. Case and outer whitespace accepted; never use reverse/obverse or translated names. Example: front.
`house`	No	Grading house: PSA, BGS, CGC or SGC; TAG is excluded. Case/outer whitespace accepted by the service. Example: PSA (psa also accepted).

Output Schema

TableJSON Schema

Name	Required	Description	Default
`summary`	Yes
`tag_note`	Yes
`standards`	Yes
`disclaimer`	Yes
`rounding_rule`	Yes
`normalizations`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed10 schema fields changedOct 6, 2026

addedInput schema / properties / face / description

Added value: +"Face: front or back, in English. Ask the user if unknown. Case and outer whitespace accepted; never use reverse/obverse or translated names. Example: front."

addedInput schema / properties / face / examples
```
Added value: +[
+  "front",
+  "back"
+]
```

addedInput schema / properties / house / description

Added value: +"Grading house: PSA, BGS, CGC or SGC; TAG is excluded. Case/outer whitespace accepted by the service. Example: PSA (psa also accepted)."

addedInput schema / properties / house / examples
```
Added value: +[
+  "PSA",
+  "BGS"
+]
```

addedOutput schema / properties / normalizations

Added value: +{
+  "default": [],
+  "items": {
+    "additionalProperties": false,
+    "properties": {
+      "field": {
+        "type": "string"
+      },
+      "input": {
+        "type": [
+          "number",
+          "string"
+        ]
+      },
+      "note": {
+        "type": "string"
+      },
+      "ratio": {
+        "type": "string"
+      }
+    },
+    "required": [
+      "field",
+      "note"
+    ],
+    "type": "object"
+  },
+  "type": "array"
+}

addedOutput schema / properties / standards / items / properties / face / description

Added value: +"Face: front or back, in English. Ask the user if unknown. Case and outer whitespace accepted; never use reverse/obverse or translated names. Example: front."

addedOutput schema / properties / standards / items / properties / face / examples
```
Added value: +[
+  "front",
+  "back"
+]
```

addedOutput schema / properties / standards / items / properties / house / description

Added value: +"Grading house: PSA, BGS, CGC or SGC; TAG is excluded. Case/outer whitespace accepted by the service. Example: PSA (psa also accepted)."

addedOutput schema / properties / standards / items / properties / house / examples
```
Added value: +[
+  "PSA",
+  "BGS"
+]
```

changedOutput schema / required

Previous value: -[
-  "standards",
-  "rounding_rule",
-  "tag_note",
-  "summary",
-  "disclaimer"
-]New value: +[
+  "normalizations",
+  "standards",
+  "rounding_rule",
+  "tag_note",
+  "summary",
+  "disclaimer"
+]

First observedOct 1, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations already cover the read-only/idempotent safety profile, but the description adds substantial context beyond them: supported houses, TAG exclusion with an instruction to explain proprietary assessment, the SGC back empty-band edge case with a 'never invent one' guardrail, and the official/interpreted/approximate return status. It does not contradict the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the critical 'USE ONLY' constraint and tightly packed with rules, but it reads as a dense run-on block. Nearly every clause earns its place, though the sentence count could be trimmed for readability.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only lookup with an output schema, the description is complete: it names the supported/unsupported houses, the optional-param default, the face-unknown ask-first rule, and even summarizes the return status fields. Nothing needed to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with enum descriptions, so the baseline is 3. The description still adds meaning: both fields are optional and '{} returns all', case/whitespace are accepted, and it clarifies the rejected aliases (reverse/obverse, translations).

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The opening 'USE ONLY for questions about published THRESHOLDS, tolerance, rules or SOURCES' states a specific resource and scope, and it explicitly distinguishes itself from the sibling grade_centering. An agent can tell what this returns (standards/sources, not a grading) without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides explicit when-to-use, when-not (do not grade supplied numeric ratios), and the named alternative ('use grade_centering instead'), plus edge-case routing ('If face/axis is unknown, ask first without any call'). This is a complete routing instruction set.

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

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